I was lucky enough to play with the 3DS in London last week, and I was blown away. The games that impressed me most were Zelda, and SSFIV3D.
Personally, I'd like to be able to buy a DS-3... which would be a 3DS without the 3D screen. That would reduce the cost some. Right now, the only platform specific game I plan on buying for a while is Street Fighter IV, and I plan to turn off the 3D and leave it off. What interests me much more about the system is the proper online multiplayer and the better processing, which allows better games such as an excellent port of Street Fighter IV. Other than that one game, I really doubt I'll play much else on it besides the Zelda and Mario Kart titles, as well as the DS games I already have.
I'll place my bets on novelty, but that won't stop me from having Street Fighter IV multiplayer in my pocket everywhere i go. =)
The 3d however is supposed to be awesome! People nearly seem to downplay it! Kinda weird!
Also, I am excited and think it will do well, the tech is awesome and lots are giving it credit even though at times it gets downplayed. The AR sounds amazing and just fun! I can't wait, getting one launch day