PS3 has pretty graphics and noise, but not a large variety of good disc games. Like the Xbox 360 and Wii, you can buy small games online, although I find myself enjoying these games more than the competetor's games for a wide variety and pretty much something for everyone. Your wireless controllers don't need batteries, which can help you save alot of money and AA batteries. Only some of the models of the PS3 are backwards compatible, though.
Xbox 360 overheats alot (haven't gotten the new model, supposedly overheats much less), and excluding the games you can buy online, most disc games are just rated Mature and mostly just FPS games and things of the nature. Online also costs money, unlike the other two.
Wii has motion control and some decently user friendly controllers. It has a game libruary of more casual games though. Online, you can buy older games from the earlier generations of consoles to play on your Wii using your Gamecube controller or a "Classic Controller" which you can buy at retail stores, which is pretty much like a SNES controller, except with two brown townog sticks.
I personally find myself playing the PS3 and the Wii, mostly because my Xbox can't go five minutes without overheating
