What's your favorite music to play to?

Don't get me wrong, I think some of the background music in many of the MMOs I've played is downright fantastic, full of sweeping moments, uplifting passages, and sections of near-earworm quality. However, everyone's taste is different; the same piece of music cannot appeal to every player equally well. And there are, regrettably, moments when what the game has for you to listen to just doesn't do justice to what you're feeling at the time.

So, what do you put on instead? Do you prefer to have some Alice In Chains for those dungeon crawls? Indulge in Beethoven for battleground free-for-alls? A little Kraftwerk for ... for craftwork? Or do you just let whatever's in the queue play on? I'm curious; lemme hear it!