good choice. the 360 has some excellent games out on it right now, and if you want to play with friends you can do so at home or on xbox live (no online gaming yet with wii, and ps3 online is a joke).
if you like driving games you should definitely pick up project gotham racing 3, that game is sick and is a lot of fun to beat and unlock cars. the online for it is pretty fun too. the newest burnout is also a lot of fun, and great to play with other people.
my suggestion with the wii is to wait a bit to get one. i have a feeling that the motion sensing wiimote will have it's novelty kinda wear off after a week or two, and you may tire of it quickly . i'd suggest playing it a few times first before buying. plus, there isn't any online play for another 2 months or so anyway.
anyone who gets a ps3 now is making a very poor decision imo. really only one launch game worth playing that you can't play on the 360, and the graphics don't look any better (in some games they actually look worse), the online is shitty, can't listen to your own music while you play, can't download while you play, etc.
so my suggestion is this (sounds like you're already on the same page as me, though)- get a 360 now, get a wii in january if you still like it, and get a ps3 in the summer/fall of 07 (when the games that are coming out actually look like they're on a console with twice the processing power of the 360)
ibiaintreadinallthatshit