>>Ummmm. lest we forget...urrr...Robert Plant? He set the standard, IMO.
Ian Gillian predated Plant, by only a few years (IIIRC, YMMV).
But yeah, how can anyone forget Plant??
Interestingly, Led Zep got a lot of their sound from muslim music. Remember, there was a time when islam was a source of scholarship and science. But they gave that up and made their religion a gutter religion.
Off topic, but a “Led Zeppelin Night” for Idol would be awesome! Robert Plant or Jimmy Page (or both) could be the mentors.