Right. Here's a thing that I know a few gamers share with me: turning off crappy in-game tunes to spice things up with your own music.
For example, fiddly RTS games are best played with some early 20th century Jazz, maybe Django Rheinhardt or similar.
Or, when you're feeling apocalyptic, playing Call Of Pripyat is good with a Godspeed You! Black Emperor audio backdrop.
That said, some games I can't have music on at all, like any competitive multiplayer FPS.
Anyone got any others?