If you are making quick broad generalizations, such as people who listen to Country are this or people who like hip-hop are that, then those are just stereotypes and not of much use.  But like anything else, if you are willing to go a bit deeper and talk about specifics of what someone likes and why, it is a great way to make a connection, you can learn a lot.  Are they moved by lyrics?  Does a certain type of musicianship touch them?  Do they like southern soul from the 60's?  Are they more likely to listen to an album or a mix tape or shuffle on their iPod or play the radio?  These are all conversations that can lead to a much more revealing discussion about character. 

What's that?  Is this a Cher record?  Do you think I'd put on Cher? Do you really think I'd even buy Cher records?  GET OUT!  Get out and don't come back!  You insult me!

Eh, kind of iffy on this one, it may or may not reflect them.
~Keely

Not sure if I agree with this one fully, either.  Just because you'd like the same radio stations as someone else doesn't mean that there's a lot in common between the two people, and more often than not I find that people tend to misjudge others based on musical preferences (for instance, assuming that listening to hard rock or rap defines someone as being somehow less intelligent, or listening to country music somehow means you're conservative.  Most people I know don't have the presumed characteristic traits that are generally assumed by musical preference).

That's a hard one ~ I, personally like most music (with the exception of Gregorian Chants), but I think that you can like a song for it's beat and how it makes you feel, even if the lyrics are sub-par (especially that stupid BLUE song!).

I think it's a real good way. It's like I've heard and tend to believe, you are what you listen to.