I used to listen to nothing but metal when I was a teen. I don't mean bands like Megadeth and Metallica who are considered "pop metal" (radio friendly 'metal') but music like Abyss, Morbid Angel, Corpse, Slayer .. bands that make your mother faint at just the sight of the gooey cover art of the deep growling vocals.
Of course, once I became a Christian some of the bands (well, all of the ones I mentioned) kind of went on the side line. Not exactly music that is edifying of the spirit!
But I found other bands that I could listen to: Living Sacrifice, Zao, Training for Utopia (now Demon Hunter), Extol .. and other extreme metal bands. I was happy.
I'm getting older now (well, I'm 30) and I have to say my music style has changed as I got older. I definitely still enjoy the metal (listening to Zao-Funeral of God right now), but I listen to a lot more mellow music than I used to. Soundscores, ambient electronica even the dreaded pop.
It's amazing what your mind decides to listen to after a while. It changes what it enjoys. Really, it's kind of interesting.
Have you noticed any changes to your music tastes as you age a bit?