I have to listen to something ( music, TV ) 'cause I can't stand silence XD
Sometimes I just go to South Park's official site and 'listen' to the episodes - I turn the volume to a level I can hear the sounds but it doesn't bother me while reading
I do, but only when I think a song will fit the scene.
For example, when reading Fruits Basket, I put on the different songs from the anime soundtrack depending on whether or not it fits.