There are a number of accessories from Apple and other manufacturers to help make it even more indispensable.
Because the new phone has new dimensions, a new Lightning interface, and was only just released, it'll be a little bit before we see widespread release of accessories.
In the mean time, check these out.
Lightning to USB cable, so you can charge up wherever you are
It's always a good idea to have a spare cable around for syncing and charging when you travel. Since the iPhone 5 has a totally different plug, it'll be a long time before you find plugs in places like hotels, airports, and cars that work with it.
A must-have for a traveler, this charging brick lets you keep your phone juiced on the go using your sync cable. The Lightning/USB cord doesn't come with a plug for the wall, so you'll have to pick up one of these too.
In a controversial move by Apple, the iPhone 5 makes use of Apple's new Lightning interface for syncing and charging. If you want to use some of your old cables, you'll have to buy an adapter. Unfortunately, Apple's adapter costs a whopping $29. Ouch.