If I was fighting an Irish guy, I'd definitely go with "Danny Boy" and while he was crying, I'd knock him the f-ck out. Of course, it might be tough 'cause I'd be crying, too.
If I was fighting one of our friends in the gay community, I'd go with Rocket Queen by GNR 'cause it makes me crazy strong, and well, it's got "queen" in the title. What can I say, I'm a crowd pleaser.
Otherwise, I'd go with white noise 'cause it totally makes me want to kill somebody. (Seriously, if you ever need information out of someone, tie them to a chair and play white noise. They WILL break.)