I haven't gotten any sort of music setup on my bike, but I would tend to agree with Metallica, some NIN, various Bon Jovi, basically anything that's loud and has some aggressive tune to it. I also like good techno as well. At least, that's my favorite driving music for when I was driving around in my modified Jag, I'm going to assume my tastes will be the same on my motorycle.
POD, Beastie Boys, anything with a good rock beat. Sometimes I get in the rap mood too, which can mean just about anything. DMX and Limp Bizkit used to be faves, but haven't listened to them in a long time.
It's not always the safest, but I do like to listen when I ride, especially on a longer trip.
I'm surprised to see so many people listening to music while riding. My buddy had his ipod w/ him on a ride and I thought he was nuts. I can *maybe* see it on a long highway trip, but going out and actually riding, its hard for me to comprehend it being safe, and maybe even distracting.
hmm i havent tried it either and i do have a mp3 player i use at the gym. well i just use what it has on it
system of a down
crusty deamons of dirt sound track
ehh theres more but you get the point