Except that's not always the case, now is it? Sometimes there's an MMO with a gifted composer who crafts tunes so ear-catching that you even listen to them (gasp) outside of the game. Sometimes there are MMOs in which you consider the soundtrack to be an essential part of the game experience, and refuse to ever disable it.
For today, we want to hear about your favorite MMO soundtrack. Which is your favorite? Are you in love with any particular track? Have you ever gone to great lengths to obtain a particular piece of music for your MP3 player or a CD? What score will you refuse to mute, even when a cute elfish vixen or lad comes up to chat?
(Bonus points to commenters who provide a YouTube link to their favorite scores -- and to the genuis who thinks that this is a great time for a Rickroll, well, call this a preemptive strike.)