In terms of graphics? For the forseeable future none. Killzone's smoke, particle effects lighting are really a good bit above anything that is available on 360 as far as videos can show, I mean putting the really expensive CELL chip into the PS3 must have been good for something. If an expensive show-case game like Killzone2 cannot outclass the 360 nothing will.
In terms of sales we will see Halo3 will most likely have much bigger sales, the 360 is still a bit of a Halo console. In gameplay terms I expect that Cod4 and Cod6 will still be better.