PS3 has plenty of quality games. I guess it just depends on if you like online play. I think Halo and GoW suck, and CoD sucks on consoles imo so online play isn't terribly important to me at this point.
IMO, the PS3 has one quality exclusive game. The 360 has a couple handfuls. And it's not just online play. GoW, Mass Effect, Fable, Too Human, all depend on single player (with coop as an option) to make a great game. Look at XBLA. A game called Braid just came out and Gamespot gave it a 9.5. A really good score for just an arcade game.
Good thing is most 360 exclusives will be (or have been) released on PC.
So how can you call them exclusive?
Because the PC isn't a competitor.
Oh, come on. I'd rather play those games on PC than 360, just for the keyboard/mouse factor for FPS. I wouldn't consider a game I can play elsewhere "exclusive", JMO.
In any event, I tend to play more non-exclusive games. I have no interest in Halo (it sucks IMO) and those other games, but games like Soul Calibur 4, GTA4, NCAA/Madden, etc, so I don't see how the library is such a huge advantage. It's not.