Music experts have long debated who exactly spawned that loud, angry beast that is heavy metal, but most everyone agrees that Led Zeppelin are the genre's absentee forefathers. Yeah, go ahead and scrunch your nose, but it's true in a way: Led Zeppelin, along with Black Sabbath and Deep Purple, popularized over-amplified blues, creating the template for the "heavy" in heavy metal. But when the late '70s brought the New Wave of British Heavy Metal along and sped up things, England's Diamond Head was leading the pack, drawing a firm line between the bluesy stuff and the tough new stuff. American metal gods Megadeth and Metallica cite them as an early influence, and it's evident. Diamond Head's grandiose, mythical lyrics met dark and dreary guitar riffs in 1976, years before Metallica was even a spark in James Hetfield's gargantuan noggin. But for whatever reason, Diamond Head never seemed to reach their full potential. Some say signing with MCA was the wrong move. They wanted the band to sound more poppy and commercial. Others say that Diamond Head's hometown base, 130 miles outside London, was too far from the "scene." One thing is for sure: Metallica's popularity and subsequent inclusion of Diamond Head jams on Garage Inc. bolstered the band's street cred.