I can't believe you guys are arguing over graphics ...
In the grand scheme of things the XBox 360 and PS3 have a far smaller gap in noticeable graphical performace than any generation before; the difference between the N64 and Playstation was huge, and even the difference between the XBox/Gamecube and PS2 was pretty dramatic. I honestly don't think you will be able to tell the difference between the graphics of both systems when you are actually playing the game; certainly, one system may look better in screenshots or in videos (and one may have a slightly better framerate) but you probably will not notice it while you're occupied with playing.