Johnny Cash - God's gonna cut you down.
Or For Whom the Bell Tolls. Beastie Boys Sabotage works great too.
Ive always wondered, if you go in there with something like Maddona's Like A Virgin...that would screw up with the other guy's head for a bit, no? take his mind off of fight mode for second. Of course, in your mind you relate the song to 1000 years of torture in the darkest corner in hell, and all you have to do to end it is win.
Man carcass in alley this morning...