I like some punk rock, and not that pussy blink 182 pop shit. I am talking minor threat, fugazi, some NOFX can be good, pennywise, old school bad religion.
For metal, some slipknot is cool, older pantera rules.
Often though, I find myself working out to the old rock and roll thats played over the gym radio, and sometimes they even have some oldies going.
In reality, the music probably has 0 to do with my lift session.... its all about hammering out the reps!