My main thoughts when I bought it were that I would use it as a tablet to take handwritten notes in meetings and to manage my many lists. I wanted the functionality of a tablet computer, with the size and lighter weight of the old HP TX1100 tablets where you could detach the keyboard.
I am now finding that I use it for those things, but also to amuse myself on long plane trips between North America and Asia. (Last year I logged 123,000 miles.) I use it as an e-book reader. I also download magazines, as airplane trips are about the place where I have time to indulge myself with magazines. (I love the Zinio app) The iPad is a lot lighter than a half dozen magazines would be!
I also use it as a platform for watching movies. Some airlines still do not have personal screens, and those who do, often show movies that I already saw. Also, I sometimes travel the same route a couple of times in the same month, so I go through the ones that I have not seen before pretty quickly. I like downloading my own movies via iTunes and watching them on the iPad. Some I buy from the iTunes store and some I import from my own purchased DVDs via a conversion software that is on my laptop.
I don't play a lot of games, but I do enjoy Sudoku and Bookworm, a PopCap game that is really intended for iPhone, but which functions pretty well on iPad as well.
I hav yet to get the email function to work for me, but I hope to be abel to use it for email, as well.
And of course, for browsing the web.
....mostly just web surfing blogging and videos. Too bad it's more of a consumer product than a creation machine. Still love it though. 
