PS3 & Xbox 360 still not out, you can't predict the choices of games yet... but a point to note is the culture, japanese loves RPG & storyline games, americans are into FPS and action kinda games... so see what type you like, there is also games that are multiplatform, so i think i no need to separate them...
but from PS2 & Xbox, i can say that PS2 have more games than Xbox by a hell lot, just check out every week how many PS2 games is released versus Xbox...