I own a PS3 and I love it. It is a great Bluray player, which was one of my primary reasons. It has built in wireless and I love the PS controllers as they have not changed. However, the PSN network is not that great especially if you play alot of multiplayer online games, especially first person shooters. I believe hardware wise it is superior to the Xbox.
On the other hand, Xbox has a superior network that you do have to pay a yearly subscription to if you want to play online games. It has Kinect, which is a REALLY popular and cool item. I believe the new Xbox model has built in wireless. The library for Xbox is larger, I believe.
It is really up to what type of gamer you are and what you intend to use it for. I prefer the PS3 because I am primarily a PC gamer and the PS3 has great looking racing and fighting games, which I do not play on PC. Uncharted is an outstanding series that I have enjoyed. Then again Xbox has Gears of War, which is a huge hit. Just do your research and test out some games at a buddies house or at a retailer.