I used to be a big metal fan. I liked a lot of the classic bands, i.e. Zeppelin, Sabbath, Deep Purple, Uriah Heep, Grand Funk Railroad, Mountain, KISS. I also liked the first wave of bands that came out of the 80s LA scene, i.e. Van Halen, Quiet Riot, Motley Crue, Ratt, Guns & Roses, along with bands that started in the 70s but didn't hit it big until the 80s, i.e. Twisted Sister, Judas Priest, Iron Maiden.
Nowadays I rarely if ever listen to metal, for several reasons. First off, many of those first wave bands get played to death on classic rock radio nowadays (Zeppelin in particular), so I've gotten sick of hearing them. Hair metal has been assimilated into that format too, which makes me like it even less. Second, I liked many of those LA bands back when I really didn't know any better. It's a little embarrassing for me to have to admit that I used to like such mediocre bands as Quiet Riot, Motley Crue and Ratt. Now I find them ridiculous. Third, I've grown to like stuff that's either poppy or rootsy, hence my current obsession with garage rock and power pop. I really wish I had gotten into the Ramones back when I was in high school, because they are a band that truly speaks to me.
However, I do have a few exceptions...I like UFO, because they're more of a cult band, and I still think "Appetite for Destruction" by Guns & Roses is a masterpiece. I also still like Aerosmith, Cheap Trick and Hanoi Rocks. All three bands tend to get lumped in with heavy metal, but I disagree with that. Aerosmith was a traditional rock'n'roll band rooted in blues; they were slightly heavier than the Stones, but not nearly as edgy as the New York Dolls. Cheap Trick was a power pop band that did sound heavier live, but I still don't think of them as metal. Hanoi Rocks almost defies classification, so I just think of them as a very cool rock'n'roll band, nothing else.