ill give you two options. 1 you flip a coin. heads xbox tails ps3. or 2: pick one that you have the bestest friend on. im stuck i have a bro on xbox and a best friend on ps3. but ill likely get it for both. who cares if you have to wait a month later for dlc.
If you don't care which system its on, you should definitely go with the playstation 3.
I owned an xbox360 and my budds and I always got down on some Call of Duty 4/World at War---
But when my older brother bought a ps3? I dumped that xbox like a cheating girlfriend with bad breath. I knew i'd have more fun with my brother than anybody else. It comes down to fun value. I can't even play call of duty without my ps3 buddies on. Its just no fun.
So to play with your friends plus its free online to do so with? I'd definitely say to go with the playstation 3. Playing alone will get awfully boring. Fast.