Just to chime in on the "Oh, you can't hear things as well, so you will surely die" argument... It is highly recommended to wear earplugs while riding motorcycles, as it elimates the extraneous noises of traffic and wind and only focuses on the noises at hand, like a close vehicle, or sirens, or other noises like that...
So, earbuds that are noise eliminating, kept at a low volume, are actually quite safe to use... At least, that is what has been taught to me... Now, if the music itself causes you to lose focus, that is another thing altogether, but the actual wearing of the earbuds to eliminate noise is actually better than nothing.
As far as music, I'm a fan of Tool, Sigur Ros, Pantera, Rage Against the Machine, Dethklok, Eluveite... Really, it just depends on the mood.
