Without even looking at the technical side of things, so far I have been *much* more impressed (graphically) with 360 games than PS3 games.
Part of this is because the incredible hype that Sony built up over the console. I had a general expectation for it to blow the 360 away, and if anything - it has been the other way around.
Now obviously, the 360 has been out for longer - so tools, optimisation and coding techniques are more mature on the 360.
But until this changes (and PS3 games start looking significantly better than 360 games) I (and most other gamers out there) will continue to undervalue the PS3.
(Why spend more on something that is not as good?)
I commented on this 6 months ago, and nothing has changed. This Xmas is absolutely vital to the console wars this generation - primarily for this reason.