Someone started a thread with suggested class theme music in the General forum a day or so ago. That inspired me, so I've spent roughly the last two days since then putting together a rather exhaustive list of music to listen to for all different elements of the game. Incidentally Pike, this is also why you haven't seen me in-game since then, possibly. ;-)
Some of this music is rare and difficult to find, although most of it will be searchable on Google by name, and you can then find how to obtain it from there. Also, in case this is necessary...I'm listing the names of songs only; so I'm not infringing copyrights.
This also probably isn't entirely finished yet, either...I'll keep adding to it for a little while yet.
BM Hunter:- Black Betty, by Ram Jam.
Night Train, by Guns 'n' Roses.
Mescaline, by 1200 Micrograms.
The Pokemon Theme.
Cotton Eye Joe, by the Rednex.
Gettin' Drunk, by the Beat Farmers.
Marks Hunter:- Moonlight Sonata 14, by Rave over Beethoven.
The Dominoes Fall, from the V for Vendetta Soundtrack.
Playing to Win, by John Farnham.
Batman Begins Main Theme, from BB Soundtrack.
Survival Hunter:- Baraka Spirit Zone, by Etnica.
Terminator 2 Main Theme, from T2 Soundtrack.
You Can't Kill Me, by Mojo Nixon.
Nurture My Pig, by the Reverend Horton Heat.
Swamp Thing, by the Grid.
Savin' The Day, from the Ghostbusters Soundtrack.
Druid:- Contradanza, by Vanessa Mae.
Power of Celtics, by Shiva Shidapu.
Feral Druid:- The Animal Song, by Savage Garden.
Cat Druid:- Whenever, Wherever by Shakira.
Send Me On My Way, by Rusted Root.
Bear Druid:- The Bare Necessities, from the Jungle Book soundtrack.
Resto Druid:- Night In That Land, by Nightnoise.
Boomkin Druid:- Ride On Time, by Black Box. (Semi-rare now)
Walk This Way, by Aerosmith and Run DMC.
You Spin Me Right Round, by Dead Or Alive.
Mage:- Attack - Plastix, by Bexta.
Friend Like Me, from the Aladdin Soundtrack.
Be Like Mike, by Gatorade. (Pyroblast ;) Rare - Email me if you can't find it)
Big Blue Dress, by Cranius (On YouTube)
Priest:- Mea Culpa, by Enigma.
Do You Really Want To Hurt Me? by Culture Club.
Holy Priest:- Almost Unreal, by Roxette.
How Do You Do, by Roxette.
Hero, by Enrique Eglasias.
Bed of Roses, by Bon Jovi.
Shadow Priest:- Spybreak, from The Matrix Soundtrack.
Operation: Blade, by Public Domain.
Arabian Nights on Mescaline, by Infected Mushroom & GMS
First Impression, by Dave Joy.
Salvia Divinorum, by 1200 Micrograms.
Rogue:- The Last Ninja, by Magnus and Erik Band. (Rare - Email me if you can't find it)
Mortal Kombat, by Utah Saints.
Spin That Wheel, from the TMNT Soundtrack.
Punch In The Face, by Frenzal Rhomb.
One Jump Ahead, from the Aladdin Soundtrack.
Everything About You, by Ugly Kid Joe.
Bad Boys, by Inner Circle. (Troll Rogue)
"Dirty Deeds Done Dirt Cheap" by AC/DC (Suggested by Josh)
Warrior:- Working Class Man, by Jimmy Barnes.
All Fired Up, by Pat Benatar.
Thunderstruck, by AC/DC.
TNT, by AC/DC.
Paladin:- The Touch, from the Transformers (1987) Soundtrack.
Superman Theme, by John Williams.
Big Time, by Peter Gabriel.
It's Not Easy To Be Me, by Five For Fighting.
St. Elmo's Fire, by John Parr.
Warlock:- Isolated, by Chiasm.
Touched, by Vast.
Forsaken, by Disturbed.
Hunger, from the Transformers (1987) Soundtrack.
The Imperial March, by Metallica. (Orc Warlock)
Shaman:- Sweet Lullaby (Apollo Mix) by Deep Forest.
Earth Tremors, by Fractal Glider.
Red, by Endorphin.
Divine Moments of Truth, by Shpongle.
Arcazection, by LioZ. (Old, impossible to find, but awesome. Email me for it)
UK USA, by Eskimos & Egypt.
Orc National:- Barbarian Horde, from the Gladiator Soundtrack.
Troll National:- Dreadlock Holiday, by 10cc.
Tauren National:- Ly-O-Lay Ale Loya (Circle Dance), by Sacred Spirit.
Forsaken National:- House of 1,000 Corpses, by Rob Zombie.
Dwarf National:- Protect Your Mind, (Braveheart Theme) by DJ Sakin.
Gnome National:- Hook Main Theme, by John Williams.
Goblin National:- Space Pussy, by Hallucinogen.
Night Elf National:- Contradanza, by Vanessa Mae.
Human National:- Kingdom Skies, by Jase. (Old, impossible to find, but awesome. Email me for it)
Blood Elf National:- My Michelle, by Guns 'n' Roses.
Draenei National:- On Sacred Ground, by Yanni.
Zone/Area Music. (This is by no means exhaustive; just a couple I've come up with)
Hillsbrad Foothills:- And Then They Start To Dance, (Dumonde Mix) by DJ Snowman.
The Crossroads:- Egyptian Nile Music, by Soliman Gamil.
The Wailing Caverns:- The Cobra's Dance (Fallahi Rhythm) by Phil Thornton and Hossam Ramzy.
Camp Taurajo:- White Whisper, by Deep Forest.
Ratchet:- Deep Blue Sea, by Brian Eno.
Man of Colors, by Icehouse.
If You Leave Me, Can I Come Too? by Mental As Anything.
Tanaris:- Desert Storm, by Infected Mushroom and Holymen.
Bloodhoof Village:- Stomp Dance, by Music of the American Indian.
Desolace:- Baraka Spirit Zone, by Etnica.
Razorfen Kraul:- Shredder's Suite, from the Teenage Mutant Ninja Turtles Soundtrack.
Stranglethorn Vale:- Suneater, by This Morn' Omina.
The Hinterlands:- Rain Song, by Myth.