Best online console shooter ever.
Controls are immaculate, with the slight edge going to the 360, mainly due to it's controller's design. The graphics are almost identical between the two systems and therefore provide very little to compare. The online is clearly going to be ultimately better on the 360 due to its paid service, constant updating, superior communication through live chat, and etc.
Call of Duty 4: Modern Warfare is a gem in any gamer's lineup, whether you enjoy shooters or not, you're bound to have a good deal of fun with this game.
The campaign was rather disappointing in its depth, as it was fairly short, however the online play more than makes up for it. This seems a lot like a game that was geared for multiplayer with a campaign tacked on to it. Despite that notion, the multiplayer easily runs circles around anything else that one might play.