You can obviously do all 3 on both. But if you aren't going to be gaming often I'd consider that you'll have to pay a membership fee for XBOX Live to game online but you won't with a PS3. May not be a big deal to you but it's always something to consider when talking about casual gaming.
Another thing to consider is the PS3 has a Blu Ray player and the 360 doesn't.
You really can't go wrong with either of the two systems but for a lot of people who are casual gamers and want to watch movies the Blu Ray player in the PS3 is the difference.
This post was edited on 1/23 at 11:54 pm