I think it's interesting that when people are dating or trying to get to know one another that one of the first questions asked is "What kind of music do you like?"
It seems that people choose their friends that they hang out with and people they date by comparing favorite singers. I don't think I've ever gone on a date without asking the girl what kind of music she liked, or what radio stations she liked (well, back before I was married anyway). You seem to be able to learn a lot about someone by looking at their CD/MP3 collection or the presets on their radio.
Take my parents for example, they pretty much only listen to LDS music. Or Rich, my old roommate, that only listened to hardrock and country (and probably secretly liked Britney Spears but would never admit it, haha). Larry only listens to 80s pop. Jason prefers Trance. Brinkerhoff - Bob Marley and Saturday Night Fever. The music people like says a lot about them.
I think that I'm a mystery because I listen to everything - except reggae, polka, and hardcore mexican music (with the trumpets and bad singing), all of which I find highly annoying.