as long as u like 3 person shooters xbox is the better choice. and it comes with a 2 year warranty and has the better quality games. the bad thing about it is that u have to pay for the online gaming
XBox360 is the best in my opinion. Generally it seems that games ported between systems look better on 360 than PS3, and XBox has more exclusives that interest me, like Halo and Gears of War, among others. 360 also seems to have a better game variety, and though that may change in the future, right now 360 is most promising.