I've never been a metalhead, per se... but I started listening to underground metal of the non-industrial type when I was 17 in 1998. Before 1998, I mostly hated metal, because all I had heard was thrash and power metal, and I still hate those styles more than pretty much any other types of music.
Of course, I loved bands like Ministry, Godflesh, early Pitchshifter, Treponem Pal, November 17, and Rorschach Test... basically a lot of industrial metal.
After 1998, I heard My Dying Bride and Anathema, and I started listening to doom and black metal very often. I still do, but now I also listen to a lot of other styles of music I didn't listen to back then, like emo and country.