People are forgetting that for Americans it will be just more than a month till we can play X360, and for Europeans just under two months... I honestly can't see the PS3 arriving here for at least another year. There's no real comparison here, in terms of games the Xbox 360 dominates the PS3 simply because we actually know what's going to be released. It may very well turn out that the PS3 has a better lineup when it is released, in case you Sony fanboys want to tackle me for what I just said.
Remember that the PS3 will have to compete with its launch titles versus the X360's full year of released titles. Right now, I can say that there are plenty of good games for X360 that will be released at or around launch. I can also say that it appears there will be several good games for PS3... when it comes. Those include MGS4 and, of course, the next Gran Turismo.
The X360's spotlight 'launch window' (aka pre-holidays) games are thus:
Ninety-Nine Nights
Kameo
PGR3
Test Drive: Unlimited
Gears of War
Perfect Dark: Zero
Saint's Row
Elder Scrolls IV: Oblivion
Quake IV
Call of Duty 2
Dead or Alive 4
Full Auto
NFS:MW
Ridge Racer 6
Tom Clancy's Ghost Recon
Tony Hawk's American Wasteland
Now keep in mind all these games aren't for everyone. There are several games up there that I'm not interested in in the least. I can say I will buy PGR3, Saint's Row, and the Elder Scrolls IV. There are plenty of 'maybes' up there, including Tony Hawk, NFS, Call of Duty, and Test Drive. PLUS all the sports games...
Just keep in mind I'm not a fanboy of either... I own both an Xbox and a PS2. Just remember that the Xbox 360 is coming out looong before the PS3, and if you want some of these great next-gen games, it would be very useful to pass the time before you grab a PS3. Which I may just do!