Right now I have nine 360 games and seven PS3 games so pretty even even though I have a couple more 360 games.
I will be buying Resistance 3, Uncharted 3 and Agent for PS3 though when they all come out; but on the other hand I'll buy the 360 version of Skyrim and probably LA Noire.
Basically I have PS3 for its exclusives, and 360 for multiplat games and online play.