Why? Is it changed from previous generations?
Most played in order:
FPS
Rhythm
RPG
Race
Action
When thinking about it it surprised me I almost didn't play any fighting games any more, although it somewhat changed after SSBB, it still holds true that I play it a lot less then I used to. Previous generations I played a lot of Tekken, Soul Caliber, Virtua Fighter and Dead or Alive ( I also played a lot of SS), but now I just can't really seem to enjoy them any more and they really can't excite me. Maybe I will play a lot of Soul Caliber though, but if I'm not mistaking it doesn't have multiplayer so maybe not.
Rhythm is a new genre I almost didn't play before (Samba di Amigo was the only one). I only just discouvered this genre with Elite Beat Agents being the first, then followed by Frets on Fire, Guitar Hero and Rockband. Although I don't think these games are the best games out there, I still enjoy the epic RPG and Shooters more, It can keep me busy for hours.
The rest is like it used to be, I still play a lot of shooters, mainly online titles like COD, Battlefield, CS (although my steam seems to be hacked, still have to mail Valve). Action a little bit less then last generation because there just don't seem to be that many this generation. Still play a lot of RPG's and I play several Racing games.