Thanks for your replies! I should add that I am a music major at university, and am quite certain that music has been a great help for me in my life. I'm looking for perspectives outside my own.
For me, music has:
1) helped me connect with people (playing duets is goal oriented as well as social, as is playing in band; and you don't have to talk while you're playing because you can't!)
1.5) helped me connected with people with interests (people can be so boring)
2) gave me a productive and fulfilling way to be by myself (I love practising)
3) given me joy (listening to music can be so fulfilling, as can performing)
4) allowed me to investigate who I am in a realm without words (improvisation, composition . . .)
I also have a sense that the impact of music goes beyond these easily identifiable ones, and have taken some books out of the library to learn more about the brain and how it is different in people with autism as well as how music alters it