Its going to replace my netbook and reading devices I think. I wouldn't use it for anything else. If you remember, a lot of people said the same thing about the iPhone, but when it came out there were people camped in front of the Apple store. I'm not an Apple fan, but I think it will be the same way. Honestly, I love seeing this. What follows is only more choices for LCD slate/tablet multifunction devices to read on and better prices too.
As a reader it is pretty hard to beat. It runs the iBook store, Kindle Store, B&N Store, Mobipocket and even more because all of that is available on the iPhone. There are tons of applications for the iPhone, and I'm betting there will be many programmers creating iPad specific applications right away. As a programmer myself, this is what we live to geek-out over.