Owning both, may I recommend the 360 if you are a "sit there for (-) hours straight" gamer. The Live is well worth paying for, along with awesome graphics. No signs of fault from mine.
The PS3 is more of a media based console but still fun. It is a "let the kids sit down and muck around on a game and then the whole family gathers round and watches a movie!" console.
I like both, but xbox 360 gets most of the attention from me