I'm lucky in that my work doesn't require loads of horsepower out of a computer. As long as I can write and resize images, nearly any device will work well.
But there are little extras, like instant messaging and news reading, that the iPad can still handle with aplomb if you use a worthwhile app.
The verdict of my experiment is that I can do an overwhelming majority of my job from an iPad, even when I absolutely need a computer to tackle more esoteric tasks like uploading an image via a web form. Using one of several Virtual Network Computing (VNC) apps available for the iPad, you can access and control your home computer over the internet.
How easily could you shed the computer and work exclusively off of your tablet? Give it a try and let us know how it goes.
A Bluetooth keyboard
If you want to do any sort of extended word processing, get a Bluetooth keyboard and pair it with your iPad. Your fingers will thank you.