I initially purchased the iPad to be used for business trips, as I travel a lot. Unfortunately, like someone else mentioned, it's a large iPhone, without the calling feature. I ended up giving it to my wife, and we use it primarily for extended bathroom trips.
It also works well as a cookbook or something to pass the time, when we're stuck somewhere (think DMV waiting area).
Despite what apple fanatics will tell you, the typing is difficult on it, it doesn't support flash, it has no internal file structure, etc. Hell, I couldn't even do word processing on it, because you can't upload the stuff anywhere. It doesn't support an upload feature. If you want to get files off, they must be emailed, or backed-up via iTunes.
For me, its a big kid toy, and nothing else.