It is very rare to come across someone with no interest in music at all. Most people have a passion or at least an interest in music and your history with music can be as complex as most other parts of your life.
It is definatly true that your taste in music becomes a large part of your overall identity. For example, most sub cultures (particularly in the west) are based on specific genres. So emos and goths have their particular musical areas that are extra strong in their identity, and same with rappers. (of course none of these things are ever set in stone, but as general patterns).
As any who have read my blog before will know, my sub culture is being a Folkie. Now with folkies there is actually a reverse problem, rather than there being a whole set of traits you can set, we are all completly different and are shared purely our particular musical genre. There are a couple of other generalisations but as a rule it is the music.
I have only been a folkie for about three years now, which is disappointing as we are currently on the tail end of the second folk revival and I have missed most of it.
My musical history however is very bizzare. I never used to bother with music until my early teens where it was actually 60's music I got into, my first ever CDs were a box set of 60's greatest hits. Through school my biggest social influences were the Goth/Punk/Geek groups and from that I picked up rock and metal. Now on the exception of Nightwish (whom I love even now) I simply could not get into it, rock on the other hand I did quite enjoy, particularly bands such as Guns ' n' Roses.
In sixform however my musical taste went through a complete shift. It was at this point I started getting into irish music such as the Pogues and the Dubliners, but I was not a full devotee at this stage.
My music taste at this point centred around a core group of bands. The Fratellis, the Black Eyed Peas, Basshunter and then a whole chorus of indivudal songs rather than whole bands.
It wa sonly in university that I unlocked the mysteries of Folk and found a whole world and culture at my finger tips that I wanted to explore.
I think even though there is no set tradition for Folk now, a fair few of us like traditional folk and with that the original celtic folk cultures.
I apprechiate all music types, but there simply is not enough time in the world to focus on them all, so I think it is nice to find one particular kind that speaks deeper to you than the others. provided you don't close your ears to anything new!