Looking back, it was 360 for a long time. That was mostly due to a lack of market penetration.
Since then, I think PS3 is pulling ahead and their increased console sales will only help.
PS3: Uncharted, LittleBigPlanet, Alpha Protocol, Mod Nation Racers, Gran Turismo, DCUO, God of War, plus some exclusive content
360: Mass Effect, Left4Dead (Valve's own laziness to blame there), Halo, Lost Odyssey, Killzone, lots of timed exclusivity
Microsoft is more than willing to pay for exclusivity, though now they have a hard time getting more than timed exclusivity. Sony as a rule won't pay for exclusivity, though they have implemented some workarounds like buying developers. This still means we'll see more exclusivity on the 360. Ultimately, it depends on what you like to play. 360 is still more FPS friendly, PS3 is more broad.
