I used to sleep to music when I slept alone.
It seems to be a personal thing though - if my girl can't sleep with music playing, it's silent slumber.
If I'm sufficiently zonked and want to drift off to some smooth, gentle music, there is always the headphones option...but I try to avoid listening to music that will energise or awaken me in the hours leading up to bedtime as I know it has the tendency to cause insomnia.
One really interesting thing about sleeping with music playing is that when I did used to regularly do it, I would frequently wake up when a long I liked came on. On the radio too, not some semi-aware playlist pattern sort of thing.
Didnt matter if I'd been asleep for 1 hour, 5 hours or it was close to time to wake up - a song I wanted to listen to very often roused me. Makes me think about the nature of sleep/wake consciousness and that idea that you can bring people out of comas by playing their favourite music. It doesn't surprise me, and i think it is really cool.
Music is amazing powerful.