If you have a interest in Halo, Gears of War,Forza, and Fable the 360 is a good place to be, but I got a PS3 about a year ago and find it a good investment due to its great and bigger amount of quality exclusives and actually love it more than the 360. The fighting games are better on PS3 IMO due to the controller.
Plus the online is free.
Without LIVE on 360 kinda makes it half a console. I have a Playstation Plus subscription and get alot of free games from it.