I don't think the graphical superiority in multiplatform games will ever happen for the PS3.
It's the 1st and 2nd party excluisives (see Uncharted) that will give the edge to the PS3 in the very near future... These are the people that have the time and money to properly code for the PS3.
The capability is there, the programming nous is not however.
PSN ID: T_Gears
End of 2009 ltd sales:
Wii = 67-68m
X360 = 38-39m
PS3 = 34-35m
Prediction: The PS3 will surpass the 360 on weekly sales after it drops to $299 on all regular weeks (no big releases).