I'm assuming it's all exclusives...
PC: Crysis
360: Mass Effect
PS3: Uncharted: Drake's Fortune
Wii: Super Mario Galaxy*
* I'm probably one of the few who isn't into Nintendo's first party games so I had a hard time picking out a game for it, but this isn't a slam against the system since for people that are fans of Nintendo's first party games it's a rocking system for them. I have a feeling since developers are scrambling to it there will likely be some pretty cool third party games I'd like a lot better than my choice but they haven't been announced yet. I also didn't bother with either the PSP or DS since I'd have a hard time finding any games for them either.