If you're an XBOX fan (Like Myself) and need some more ammo, try this: A UK psychologist performed brain scans on one human subject (yes, one) playing games on the Xbox, PS2 and Gamecube, and found that brain waves while playing the Xbox indicated a "high level of cognitive interest" as opposed to the other consoles.
Check It Out:
http://www.ananova.com/news/story/sm_544489.html