I was listening/Watching the latest WASD on my second screen, while also playing N4S Most wanted. and I quite regularly watch the EEVblog and other shows + listening to War Of the Worlds. Just to name a few while gaming.
Sometimes I listen to The Tek or The WAN Show or some music while playing The Binding of Isaac or Risk of Rain or some game that doesn't rely on sound.
Depends on the game, story heavy games i dont usually play music, or on games with extremely good soundtracks like Transistor however mechanics based games and some fps i do put music while playing them.