PS3: The list of exclusives on top of some quality multiplatform titles has meant I've played it fairly steadily over the entire year (Killzone 2, Uncharted 2, Assassins Creed 2).
2nd place has to go to PC for me, based almost solely on the PC version of Dragon Age: Origins, but also for finally getting all Acheivements for Fallout 3 + DLC.