I'm a graphic designer and currently I'm specializing in user interface design. So getting my mitts all over this new kind of interaction design is crazy-appealing to me, right off the bat.
As far as what I plan to use it for here's what I've been daydreaming about so far:
THINGS THAT EXIST ON DIS EARF, CURRENTLY
Sketching: The updated Brushes app + a Pogo stylus will be something I'll use daily. I design icons currently by busting out my moleskine sketchbook and doodling my concepts until I come up with one I like. Then I'll usually scan my best ones in and start building over top of them in Illustrator. So to be able to sketch them out on the iPad then just email them to myself (also to keep all my concepts organized within the app) is a freakin' dream come true. Also, should inspiration hit me while on the bus it'll be a lot easier to bring out the iPad then it would to prop up my big sketch book and dig through a pencil case full of colours.
Recipes: When I'm not graphic designing, I'm playing around in the kitchen with various baking projects. Currently I use Evernote to organize my recipes but picking up my iPhone and holding it up to my face to read ingredients with slippery flour covered hands isn't ideal. I'm going to make / buy a wall mount for it in the kitchen on the outside of my pantry door, right at eye level, to view my recipes. Awesome.
Reading Comics in Bed: How excited am I to use ComicZeal and read full screen comics on the iPad? Freakin' excited. That's how excited.
iWork: If I never have to see another fugly Excel spreadsheet in my life I can die happy.
THINGS THAT DON'T EXIST FOR IT YET, BUT WILL SHORTLY
Magazine subscriptions: Give me a Martha Stewart app that updates monthly with the newest issue of the magazine and allows me to clip crafts, photos and recipes all within the app. GIMMIE. Also, Entertainment Weekly. I love reading the issues but I hate wandering around my apartment at the end of the month, gathering up the issues from under the couch and in the loo, then pitching them.
Board Games: I'm a bit of a board game junkie (Monopoly, Scrabble... even the little goofy ones, like Boggle and domines.) I'm looking forward to always having my favorites on me that I can plop down on the table at a friend's house. Scene It would be great on the iPad, with the video clips built right in.
Really there's a ton of possibilities for the iPad because there's a ton of possibility for apps made for a larger screen. I'm excited to see what developers, and Apple themselves, come out with in the future.
To be fair, I'm a gadget junkie. Gadgets are what I choose to spend my hard-earned dollahs on. So I can see where this would be a monetary stretch for a lot of people.
One last thing: Those of you who are more hardware tech savvy - could a clip-on webcam be designed that plugs into the 30 pin connector and work with an included / free app? Because if so, Logitech should get ALL OVAH THAT. I do lament the lack of webcam as my family lives in BC and I'm in Ontario.