Mostly listening to my own playlist while gaming, but if I like soundtrack or if it is very atmospheric I'm listening to it... until I get bored. :] And sometimes I'm listening to some game soundtracks (Fallout, Planescape: Torment, Sanitarium, Quake and others) while I'm not gaming...
And I always have some music playing (even when I'm sleeping
), except the time when I'm watching something like movies or anime...