I can't believe I forgot to mention Black Sabbath, which I consider to be the first "metal" band. They were all big Beatles fans, and the influence shows in their first album. Sabbath are really underrated in my opinion, because people always associate them with songs like "Iron Man", but never give them credit for their more complex stuff. I believe their song "Fluff", an instrumental, is pure genius. They offer something for everyone.

Another one I forgot is one of my head-slammin' favorites, Pantera. Dimebag Darrell is my hero.

Anyone ever heard of UFO? Their song "Lights Out" never gets old for me.