FWIW, early Rush is no less heavy than any of those, but over time, they morphed into a prog-(hard)rock band. And had they not done what they did, its unlikely that prog would have gained as much of a foothold in metal as it has.
So, while many of the bands mentioned in this thread may not be heavy enough to satisfy you, the fact remains: all are either metal, key to certain elements of the genre, or inspired by metal. And knowing those details makes you a scholar of the genre, and better able to understand its many nuances.
Well said. You can not listen to, say 2112, and not classify it as metal. I had the great fortune not so many years ago to see the trio do it, in it's entirety, live in Dallas at the Starplex/Smirnov or whatever they call it nowadays. I've seen Rush three times and they never disappoint me. The first time Suicidal Tendancies opened for them in Tulsa, the last two were in Dallas and they had no opening act, just damn near 3 hours of Rush.
Their transition into prog is really what set them apart from the pack. 2112, in my mind, is the definitve Rush album. It is prog (in structure, at least) and heavy metal. The two are by no means mutually exclusive. Starting with Permanent waves the band went Prog and left metal, for the most part, behind.
Anyone saying Deep Purple isn't metal, imnsho, is an idiot. Period.
Malmsteen is metal, in his own way. He was speed metal before there was speed metal, the noodle fingered bastard.
Queen had it's metal moments, but mostly they were Opera rock, much the same as Styx. Love both bands, but I would call neither metal.
But, wait, if you like do an entire soundtrack for Highlander don't you have to be metal? umm no. I hate Christopher Lambert. I'm glad there's only one of him. I don't hate the first Highlander though.
ZZTop is more blues rock than anything else. No where close to being metal.
Speaking of blues rock, one that definitely bleeds over into Metal is AC/DC. I turned my nose up at them for years simply because I preferred the more 'intellectual' stuff (Maiden and such). I out grew my elitism/idealism, as everyone does, and am quite fond of them now.
Ok, I will now admit my one metal guilty pleasure: Manowar. Cheesy to the extreme, but damn. I don't think there are any songs that have been played more in my D&D campaigns than Black Wind, Fire & Steel and Defender.
I am an outcast on the path of no return, punisher and swordsman, I was born to burn!
Budgie- The only song I can recall is "Crash Course in Brain Surgery".
While I'm here and typing, I feel the need to say Jethro Tull is definitely not Metal. Seriously! Elandrin, you were kidding, right? I'm not saying I don't like me some Tull, but they are definitely not Metal.
Don't know if they have been mentioned, I haven't been through the whole thread, but Metal Church brings back some memories.
Speaking of memories, and some of my earlier days of gaming, let's not forget Cirith Ungol.