The vast majoriy of games on PS3 and X360 I play are multiplatforms because those are the best and eat all exclusives alive.
As for the few exclusives I like, for me Xbox360 only has got Halo as I dislike Gears and hate Fable, and Alan Wake can now be found on PC.
Great exclusives on PS3 are God of War, Heavy Rain, Demon Souls and to some extent Unharted and Ico which are decent but crazily overrated.