For sales? I'd say.
America:
PS3: FPS
360: FPS
Wii: Minigames (Or FPS if they gets some serious entrys)
Europe
PS3: Racing/FPS
360: FPS/Racing
Wii: Minigames/Racing
Japan
PS3: RPGs
360: broad spectrum
Wii: Nintendo games (Wii Fit, Brawl, Kart.)
Of course dominate doesn't = all sales. Just largest genre. For example I expect Wii RPGs to actually outsell PS3 RPGs in japan. (I think FF will get delayed... and if you don't count FF it won't be close.)