I actually create "soundtracks" for my games with music from all kinds of sources, especially if I want the game to have a particular feel to it. 95+% of all the songs are instrumental, unless it's a major theme that will be the focus of attention while it's playing.
Oh, and that Savage Tide soundtrack list would have been way more useful if it had listed soundtracks and not just song titles...
Music fits my rather cinematic style of DMing quite well, especially since I switched from D&D to Savage Worlds. I use the World of Warcraft soundtrack and Midnight Syndicate as background music, and have setlists for battles and boss battles. It's mostly video game music, and a current favorite for boss battles is Enemy's Raid from the game Tales of the Tempest.
I guess music during a game is not for everyone but I personally couldn't do without it.
When I get back to playing face to face, I'll probably use some wordless stuff from Ennio Morricone, which is epic without being a recognizable Warcraft or LotR soundtrack.