also if you like free games now and again you can get Playstation Plus which i think is a good value for that, but has horrible online support and interaction, where xbox has great online features to help playing with friends easier and more entertaining.
i have both but dont play online, and i do prefer PS3 over Xbox just because the console has more to it that fits my needs that the xbox, IE. blu-ray player, exclusive platformer games, media server for streaming movies (over connected LAN not wifi, which is way to slow to stream almost anything properly).