What is a good online xbox 360 shooter game?

I’m looking for a good ONLINE multiplayer shooter game. However, it has to be TEEN. I want one that you can talk to other people online through the voice thing, and one that is very fun.
Okay, my parents agreed to let me a get a M game = D. I was thinking COD5. Remember I’m ONLY looking for the ONLINE experience.

I don’t think there is one that’s rated “T”, the best online shooters are rated “M” like Gears of War, and Call of Duty.

Classic Game Room HD – AEGIS WING for Xbox 360 review