Apps are the cornerstone of iOS. The ecosystem is what sets Apple's mobile platform apart from its rivals, and the highest-quality iPhone apps are typically best in class.
But, like any app store, it is sometimes difficult to find out what are truly the best apps, the ones that stand out from the rest - because they offer a tool or service that is far beyond anything else available.
Sometimes the best apps are free, other times you will have to pay a little bit for them. Here we showcase the best available and offer up everything you need to know about the app and how much it will cost.
This round-up compiles our favourites, from top-quality creative tools and video editors to the finest productivity kit and social networking clients.
As always, if your essential app isn't on the list - let us know in the comments...
1. 1Password ($17.99/£12.99)
With iOS 7, Apple introduced iCloud Keychain, for entering and securely storing passwords and payment data. But 1Password is still worth investing in, for its wider support (platforms; browsers; websites) and the means to store multiple identities and secure notes. On iOS, it has its own built-in browser; alternatively, you can copy passwords to then paste into Safari.
2. Adobe Photoshop Touch ($4.99/£2.99)
This ambitious app aims to bring some of the power of Photoshop to your iPhone. Naturally, Adobe Photoshop Touch can't match the hugely expensive desktop app, but it nonetheless has a very good go for its tiny price tag, enabling you to work with layers, blend modes and a range of versatile tools.
3. Air Video HD ($2.99/£1.99)
Even the most expensive iPhone has a fairly limited amount of on-board storage, and this is a problem if you have a large video collection you'd like to access. Air Video HD server streams (and if necessary, re-encodes) files from a PC or Mac that can then be played on your iPhone; there's AirPlay support, and also the means to access your Air Video server over the web.
4. Blur ($0.99/69p)
Sometimes the best apps are the ones that offer a seemingly effortless level of elegance. Blur merely takes one of your photos and enables you to blur and save it. The result: some of the most beautiful background wallpapers you're ever likely to see, made from your own images.
5. Byword ($4.99/£2.99)
Byword is a text editor that hits the sweet spot of being both usable and simple. Its font is clear, and a toolbar adds live word count or Markdown buttons. Your documents can be saved locally, to iCloud, or to a linked Dropbox account. Output can also be exported to various formats (PDF; HTML; email) or to a blog if you buy the $4.99/£2.99 'Publishing' IAP.
6. Capture ($1.99/£1.49)
It's frustrating to miss a moment you'd like to savour forever, despite being armed with an iPhone that boasts perfectly good video recording capabilities. But getting to the relevant settings in Camera can be fiddly. Capture does away with such messing around — launch the app and it immediately starts recording; quit and the app saves the video it's shot to your Camera Roll. It might not seem much but those seconds saved can make a big difference.
7. Clear ($4.99/£2.99)
While Apple's own Reminders app is mired in interface hell, Clear shows how it should be done. Lists are managed through gestural input, and urgent items at the top use a deeper red hue. iCloud sync enables your list to be up to date across all devices.
8. Day One ($4.99/£2.99)
Traditional journals are all very well, but there's something wonderful about an app that you always have with you, into which you can save messages, images, locations and more, and then later retrieve everything via a search. Day One is beautifully designed and easy to use - best-in-class on the iPhone.
9. DM1 ($1.99/£1.49)
There are plenty of drum machines for iOS, but DM1 is easily our favourite. For beginners, there are pads you can tap and 86(!) kits to mess about with. Beyond that, there's a step sequencer and song composer, WIST, MIDI and Audiobus support, and export to iTunes, email and Dropbox.
10. Fantastical 2 ($3.99/£2.49)
Fantastical 2 betters iOS 7's iffy Calendar app by way of a superior interface, a non-hateful method of dealing with reminders, and truly exceptional event input. The app has a powerful parser, and so while adding an event, you can enter the likes of "TechRadar lunch at 3pm on Friday", watching a live preview build as you type.
11. Figure ($0.99/69p)
Figure crams Reason's rich history of classic-era electronic music apps into a shoebox. Via a mixture of dials and pads, you can create all manner of banging choons, and then export them and assault your friends' eardrums. It's a fun toy for anyone, but also has the chops to be part of a pro-musician's mobile set-up.
12. GoodReader ($4.99/£2.99)
With iOS lacking a file system, surrogates are needed. Dropbox is great for general use, but GoodReader is an excellent solution for storing, viewing and searching all manner of documents, including PDFs, text files and images. It's packed with features and can connect to a huge range of online services.
13. iMovie (free with new devices or $4.99/£2.99)
Camera enables you to do the odd bit of cropping with video files, but iMovie is an audacious attempt to bring a full video editor to your iPhone, infused with the ease-of-use its desktop counterpart is renowned for. Amazingly, it succeeds. Effects, themes, credits and soundtrack creation then provide extra polish for your mobile filmmaking.
14. Launch Center Pro ($4.99/£2.99)
More or less a speed-dial for regularly performed tasks, Launch Center Pro can be a huge time-saver. You can create shortcuts for things like adding a new Tumblr post or sending your last photo to Twitter, and these shortcuts can be arranged in groups. An essential purchase if you heavily use even a handful of the [supported apps](http://actions.contrast.co).
15. Moves ($2.99/£1.99)
There are plenty of trackers available for iPhone, but Moves rises above its rivals through automatically recognising exercise types and providing you with a daily 'storyline' of your activity. And while the app itself isn't big on data sharing, it's easy enough to get your data out via Moves Export.
16. Numbers (free with new devices or $9.99/£6.99)
When Apple first brought its office-style apps to iPad, that was impressive, but squeezing them down to iPhone size seemed impossible. Yet Numbers in particular remains surprisingly usable, not least when you create forms to rapidly enter data while on the go. iCloud sync provides access from Macs and also PCs via Numbers for iCloud.
17. Pocket Casts ($3.99/£2.49)
Apple's Podcasts app has improved since its initial launch, but still falls short of Pocket Casts. The third-party app cleverly mixes elegance and character, with a friendly, easily browsable interface. Subscriptions can be filtered, and you can stream episodes of shows you've not yet downloaded.
18. ProCamera 7 ($4.99/£2.99)
This app takes your iPhone's camera to the next level. ProCamera moves beyond Camera in offering more modes, including rapid-fire, anti-shake and night shooting; there's a dedicated lightbox for managing images; and dozens of filters are built-in, along with an impressive selection of editing tools.
19. Soulver ($1.99/£1.49)
Soulver eschews trying to recreate a traditional calculator on your iPhone. Instead, it's akin to jotting down calculations on the back of an envelope, but a magic envelope that pulls the numbers from your in-context sentences and gives you a total. Live currency conversion is built in, and you can save calculations and sync them via Dropbox or iCloud.
20. Star Walk ($2.99/£1.99)
Augmented reality isn't terribly exciting when it's a game showing a tiny alien doddering about on your desk, but when it involves the stars, it's a totally different and utterly mesmerising story. Star Walk is a guide to the heavens, but it comes to life when you overlay your screen on the night sky, enabling you to pick out constellations, planets and satellites with ease.
21. The Elements ($13.99/£9.99)
Originally the darling of the iPad, The Elements in late 2013 became a universal app, so it could be enjoyed on iPhones too. A rich, engaging digital book, it tells the story of the periodic table. Each of life's building blocks can be manipulated on the screen, before you delve into related facts and figures.
22. Traktor DJ for iPhone ($0.99/69p)
Traktor DJ on iPad is a fantastic DJ app, enabling you to work with waveforms rather than just bunging two virtual spinning records on-screen. Cramming that into an iPhone seems like madness, but somehow it works. There's more zooming and swiping, but otherwise everything's here, from EQ to tempo controls.
23. Tweetbot ($4.99/£2.99)
The king of iOS Twitter clients remade for iOS 7 is a wonderful thing. Managing to combine Apple-style sleekness with developer Tapbot's playful nature, Tweetbot is a fun, feature-packed app. As a basic client, it works, but as an app for heavy Twitter users, it excels through its flexibility and wealth of settings.
24. Vert 2 ($1.99/£1.49)
There are a lot of conversion apps about, but Vert 2 caught our eye through an interface that prizes clarity above all else. Beyond that, a combination of smart filtering and customisation cements the app's place on your home screen. And if you don't like the theme, you can easily make your own.
25. vividHDR ($1.99/£1.49)
We've never been overly impressed with Apple's HDR, and it pales in comparison to vividHDR. The basic concept is the same: stunning, vibrant photos, capturing amazing details in both highlight and shadow. But vividHDR's combination of speed, presets and 'before and after' comparisons results in better photos - and that's what really matters.
Best iPhone apps: 26-50
In all honesty, Comics is a little awkward compared to using it on an iPad, but you won't find a better comics experience on an iPhone. The app is free, as are dozens of downloadable comics - and once you run out of those, many more are available to buy. Reading works on a frame-by-frame automated 'zoom' basis, and is surprisingly usable.
Plenty of apps exist for transferring content between your computer and your device, but Dropbox is free and easier to use than most of its contemporaries. Dump files you want to sync in a folder on your computer and Dropbox for your device will enable you to access them, download them for offline viewing, and, in many cases, view them.
On using the eBay app, there's a good chance you won't go near the eBay website again. The app is fast, has great saved searches (which flag new finds), and enables you to create listings. The last of those things is also improved by the built-in bar-code scanning.
Clients to access the popular Evernote service for storing notes and ideas online are available for so many platforms that we half expect a ZX Spectrum app to be announced tomorrow. On the iPhone, Evernote is efficient and usable, enabling you to rapidly scan your notes and also create new ones.
The world's biggest social network brings a tightly honed experience to the iPhone and iPod touch, but nonetheless still enables you to access your contacts, feeds and other important information. This sense of focus makes it in many ways superior to using Facebook in a desktop browser.
31. Find My iPhone
For the paranoid souls out there (or the unlucky ones who've had their devices pilfered), Find My iPhone is a must-have download. Assuming you've a 2010 or later iOS device, you can set up a free account and locate your devices within seconds. (Note that older devices can also be added to Find My iPhone - you just need a recent one to get things going.)
Apple's GarageBand turns your iPhone into a recording studio. Previously a paid app, GarageBand now has a freemium model. For no charge, you get full access to its features, including a range of smart instruments, MIDI editing and song arrangement. The only limitation is that relatively few instruments are included, but more are available via IAP.
33. Google Maps
When Apple removed Google's data from its Maps app, seemingly half the internet went nuts. In hindsight, the decision has been beneficial, because it resulted in Google creating its own mapping app, Google Maps. Bar some mildly irritating signing-in nonsense, this is a first-rate application - the interface is straightforward, the mapping is accurate, and it's also a means of getting Street View back on to your iPhone.
34. Google Translate
Assuming you're online, Google Translate is a great app for translating text between dozens of different languages; handily, the most popular of them enable you to speak into your device and listen to translations. It's also considerably cheaper and more portable than dozens of translation staff.
If you've a large music collection, it can sometimes be difficult to decide what to listen to next. Groove tries to figure out your listening habits and cross-references your collection with Last.fm data. The result is constantly evolving automatic personalised playlists that might just change your iPhone music-listening habits for good.
Take a photo, smash a filter into it, and upload it. Instagram's service is now used by millions of people to share nuggets of visual loveliness, and the app itself is a pleasure to use, and also to browse during moments when you're not feeling quite so inspired.
Watch live TV and browse featured and recent BBC shows in the BBC iPlayer app. There's a favourites section to get easier access to your top shows, and AirPlay support for firing footage at your Apple TV. (This uses the system AirPlay functionality - start playing a show, double-click the Home button, swipe right twice, then choose 'Apple TV' from the AirPlay button.)
With iBooks on the iPhone, you might wonder why you should bother with Amazon's Kindle. After all, the app's not as pretty as iBooks, nor is there an integrated store (you buy in Safari and sync purchases to the app). However, Kindle offers a massive selection of books compared to Apple's app and the reading experience is great.
39. Movies by Flixter
Although some aspects of cinema listings app Movies by Flixter are disappointingly US-centric (notably regarding details on upcoming movies and DVDs), it succeeds where it matters. Select a film and the app figures out where you're located, lists nearby cinemas, and displays times your chosen film is showing. Efficiency can be further increased by pinning favourite cinemas to the top of the list.
Brits might rightly grumble that the Netflix selection leaves a little to be desired, but it's still a very affordable way to get a ton of TV in front of your eyes. The app works much like you'd expect: browse, watch, realise it's three in the morning - again.
The service formerly known as Read It Later enables you to save pages from websites, to read them later, bereft of the advertising and other junk on the original page. The service is free, as is the Pocket app, which downloads your articles, so that you can digest them without a web connection.
The remote for Apple TV is a bit of a joke when you need to do anything more than play or pause. Remote is a free app which provides much better control and the ability to stop yourself going mad when typing things into search fields. It'll also happily use Home Sharing to pull content from computers on your network to your device, or fire said content at your Apple TV using AirPlay.
The prospect of Nike+ but better and for free might sound unlikely, but that's what RunKeeper provides. Previously split into 'pro' and 'free' versions, the developer now generously includes all the features in one free app.
That means you can spend no money, yet use your iPhone's GPS capabilities to track your jogging and cycling routes, and examine mapping and details of your pace and calories burned. Activities can be shared online, and treadmill runs and other exercise details can be entered manually.
Shazam is an app that feels like magic when you first use it. It's deceptively simple—hold your iPhone near to a music source, and wait while the app listens and tells you what track is playing. But the sheer technology behind this simplicity is mind-boggling, and while Shazam doesn't always guess right, it's worth a download.
FaceTime is a great alternative to standard voice calls, but it's no good if you're trying to contact someone without a Mac or compatible iOS device. Therefore, Skype remains an essential download. The interface is simple and usable, enabling anyone with a Skype account to make free calls to other Skype users and cheap calls to anywhere in the world. If you're on Pay and Go, this is particularly handy, but the app also enables iPod touch users to utilise their devices for calls.
TED is brain food. The app provides access to talks by insanely clever people, opening your mind to new and radical ideas. You can also save your favourite talks locally, for even easier access, or ask the app to inspire you, based on your mood and available time.
Timers and task managers are usually designed with extreme efficiency, to the point they practically yell NO FUN ALLOWED in your face. 30/30, however, provides a streamlined, tactile interface that happens to look great, is fun to use, and that makes it a breeze to create lists and define timers. It also enables looping for anyone addicted to the Pomodoro Technique.
The official Twitter app might lack some of the features found in the likes of Tweetbot, but it does provide a sleek and simple means of using the service. It also rapidly rolls in new features from the website, such as the Connect and Discover views, along with expandable tweets that contain photos and videos.
49. TuneIn Radio
Don't bother buying a DAB radio - just install TuneIn Radio instead and plug your device into a set of speakers. TuneIn Radio has a great interface for accessing over 50,000 digital stations; it also has AirPlay support, and you can use it as an alarm clock.
The Wikipedia website works fine on iPhones, but a dedicated app is a better bet. Wikipanion is a freebie which gives you quick access to article sections, in-article search, viewing options, bookmarking, and the ability to tweet about whatever odd fact you've just unearthed. Also, wonderfully, there are no ads.