Not music, but conversations.
Not psychophrenic like, they're always my voice within my control, but it's a definite dialogue between me (person A) and me (person B). B is sometime visualized as someone I know or used to know, or is other times "faceless."
For example, as I was reading the responses, I was having a conversation in my head where I am hashing out the response that I am writing right now with a nameless someone.
At least my conversations are different and don't happen over-and-over again like a stuck jukebox. That could be annoying.
I have the same conversations in my head.
I prefer having music in my head though, even if it's a few lines looped again and again. It gives me something to listen to on my ipod instead or flicking up and down my playlist being unable to come to a decision of what to listen to.