YAY! I inspired a thread.
Also, I think to some extent it does. Look at all the people who have crafted their personalities based on various genres such as hip-hop and punk and emo. I think that those examples right there prove that music can determine one's identity.
As for myself, since I listen to a little bit of everything, I like to think it does. After all, my identity can easily be described as "being myself at all times." Then again, with all the video game music and remixes thereof I listen to, "nerd" is also highly applicable.