How much do you think you can tell about a person just by looking at their collection of music?

If you could browse through all of the songs and albums that someone has, how much do you think you could accurately describe him or her. Including phyiscal and mental aspects, personality, age, gender, where they live, etc…

What are some specific songs or genres that could give away descriptions? How about the size of their music collection, or what if the person doesn’t own any music at all? What’s a song in their collection that could throw everything off?