Rock and Roll seems uncommonly popular. I was sure that Classical would be at the top. How about film soundtracks?
A few of my favourite (and recommnedations) are:

Conan the Barbarian and one or two tracks from the Destroyer.

The 13th Warrior. This soundtrack is really excellent. If it doesn't have you horripilating like mad nothing will.

Excalibur. The pick of the Wagner crop and Carl Orff's Carmina Burana.

Blade Runner.

The Last of the Mohicans

The Lion in Winter. This is an old (but excellent) film of mediaeval dynastic intrigue and family squabbles with a soundtrack to match.

Anybody else have any suggestions?[b]

I'm a big fan of the "Fear and Loathing in Las Vegas" soundtrack when I just want to kick back and mess around on the MUD.

When I play my necro, it's almost always the 'October Rust' album by Type O Negative.

For some reason, and I hadn't realized this till I read this post, I find myself listening to the "Hunt For Red October" soundtrack when I play the mage.

All other classes, I just shuffle the mp3's in my shared folder.

BALDUR'S GATE SOUNDTRACK

I like to have really LOUD and fast music playing during a fight or something.Gets me pumped, lets me react to stuff quicker because it makes me feel like i'm in the game. But I like to be able to determine what notes are played, so it can't be too heavy. Techno is good for this. And drum solos are bad. If techno was an option I would've voted for it.

I mostly use the Nuku Nuku soundtrack, Deep Purple, Slayers Sound Bible, Offspring, the few techno singles and remixes that DON'T suck, Zebrahead, tons of Overclocked remixes, What Would Brian Boitano Do?, Brahms, Tchaikovski, Ace of Base, Bonnie Tyler, Boston, Charlie Daniel's Band, Darude, Juliane Werding, Styx, Nanase Aikawa...and that's just for battles.

For creation systems, lounging about, RPing, you can listen to whatever you want. Really, it's your life, you set the mood.

Wagner's "Ring".

Toby Twinning, an acapella-ish band, is great for RP. I wonder if there's any clients that can play and switch mp3s with triggers. A fade-in/out effect would be nice, too. Anyone know? If not mp3s, at least midi files.

Anyway, other than Toby, I have a huge playlist of what I'd call melodic rock. There's probrally a better description, but I like anything that has some melody to it, not just drums, not droning, and not with the singer bloody screaming at me for no reason. Incubus, Pearl Jam, quite a bit of Metallica, RHChili Peppers. That sort of stuff is what I use in general play, plus some other generic songs that I like and download, like Enya, a few good MIDIs, the Star Trek themes.... Music is great.

I can't seem to find it but I once started a topic exactly like this for my MUD's forums, just for fun. Here was my suggestions:

Fighting with a fierce enemy: Duel of the Fates from the Star Wars I cd.

Running with a corpse to a church to bring him/her back to life: Chariots of Fire theme song.

Playing some wind instruments?: Gheorghe Zamfir panpipe collection

Been killed and waiting to be brought to life somehow? The Jeopardy theme.

A great horde of creatures wiping out the city?: Paler Shades of Winter (not sure why that one song, just that it sounds good with it)

All i can remember at this time, will put more when i can.

Edith Piaff is the best.