[WitchdoctorDan]

I'm adding the Eminem song from CoD.


Won't Back Down - Eminem (Trailer song from Black Ops, also found in a zombie map Easter Egg.)

Also:
Welcome to the Jungle - Guns n Roses. Good for the jungles, I guess? XD
Requiem for a Dream - Clint Mansell. One of THE most epic songs around.
I Thought Inside Out - Chris Lake & Deadmau5. A nice trance/electronica song. It has that really trancey feel that makes you bob your head up and down every time.
Slayem (COD WAW Soundtrack) - Sean Murray. A short, but very epic and haunting piece. Nice for a lot of combat.
Zeros Alt (COD WAW Soundtrack) - Sean Murray. For a game set in WWII, this has a lot of synth in it! Pretty epic, not bad for sailing.

Also also:
The entire Call of Duty: Black Ops soundtrack.