Black Sabbath
Metallica-Dethlok (tie)
Judas Priest-Iron Maiden (tie)
It makes sense on initial gloss. There is no heavy metal without Sabbath. Metallica was the biggest heavy metal band in the world until Dethlok showed up (no death metal band, that I am aware of, has had an album debut in the top 30 on the Nielsen charts, and no metal band that I know of has a TV show.) Judas Priest and Iron Maiden made contributions both in style and sound that cemented heavy metal's place in the rock pantheon, as well as providing it with a tradition and template for how it's done.
But there is something missing: Led Zeppelin. The honest truth is that Zeppelin is just as important as Sabbath to heavy metal. Bands like Tool and the Deftones come from what Zeppelin brought in, Soundgarden (despite their dislike of being included as a heavy metal band) is a heavy metal band because Zeppelin was one.
Except they weren't. They were a hard rockin' band. Nevertheless, heavy metal needs that, because it needs bands like AC/DC (who influenced Slayer and Anthrax, amongst others.)
And what it got me to thinking is how rarely there really is one thing at the top of a list. They don't speak of one great sci-fi author, they talk about Asimov, Heinlein, Sturgess, Clarke, Bradbury. Is Superman the first hero? Absolutely. Is he what he is without Batman, Wonder Woman or Spiderman? Nope. Think of Steve Jobs-Bill Gates (and even those two had equals and a supporting cast.)
I don't knock anyone's drive to be the best. Some people are-can legitimately claim that spot. Not many, though. But humans tend to do our best work as a collective; scientists standing on the shoulders of other scientists, men & women making discoveries at the same time (though sadly usually only one gets credit in the collective consciousness.)
Just something interesting.
Just something interesting.