-- PS3 --
The PS3 is cheaper in a lot of different ways. The games for the PS3 are cheaper so you'll save money on that when there is a game on both the PS3 and the xBox. There is free online gameplay so you don't need to spend $50 to play online when you can do that for free with a Wi-Fi connection.
The graphics on the PS3 are better I think. It looks smoother and not so "glowy". On the 360 the graphics for NBA 2k11 are good but the players sometimes glow, its weird. Also the PS3 has Blu-Ray so you don't even need a DVD player (saves money). Alot easier to set up your PSN and with the Internet.
The controllers for the PS3 are a lot better because they are smaller so your hands can go around the whole thing. And the controllers are more sensitive so its easier to do things and they react to your every movement.
If you read this whole thing..