I've had my ipad since October -
Re: Purchase from Apple store vs. Best Buy - I bought mine from BB because they were open, and the drive to an apple store is almost an hour, and the apple store was closed. LOL I bought mine along with a 3yr BB warranty. The warranty isn't inexpensive, but it covers pretty much any way I can screw up an iPad, other than dropping it in water. I'm not sure what Apple's warranty covers.
I haven't explored too many "art" applications. OK, I've explored none. I'm a photographer, and from a photog. perspective, LightTrac, Easy Release, Second SHooter, Portfolio, and DoF Explorer are great programs. Noteshelf is a great one for writing with a stylus.