After a few hundred hours of the default music, I can't stand it anymore. One of the tracks for Wyre and both for Bedlam are still great though.
A lot of stuff. A lot meaning.. a lot. Punk rock, emo, screamo, techno, rave, trance, "unfitting" music..
YouTube - Bercy / Daft Punk Alive 2007 / Around the World - HBFS
ht*tp://www.youtube.com/watch?v=-gZ4rywbyxs
The Hoosiers - Goodbye Mr A fitting in the unfitting category of course
ht*tp://www.youtube.com/watch?v=QV8eiSA4vqc
Deadmau5 - Ghosts 'n Stuff
ht*tp://www.youtube.com/watch?v=TF2setyp_kg
Nickelback - Burn it to the Ground
Occasionally though, no music whatsoever. Just the game sounds and voice pumped way up. Somehow moments like the boss spawning behind your squad become a lot more tense when it's just your team's voices and heavy breathing of the Patriarch. Asterisks for preventing video spam >_>