Both Soundgarden and Alice In Chains should be ranked ahead of Nirvana. I hate the VH1/MTV revisionist history that Nirvana started the "grunge scene," whatever the hell that means. I owned Soundgarden's Louder Than Love and Ultramega OK years before Nevermind was recorded, and Badmotorfinger was beginning-to-end better than any greatest hits compilation Nirvana could assemble. Hell, I'll listen to Foo Fighters over Nirvana, as I think Grohl's songwriting is far better than Cobain's, and Grohl was never given the chance to fully show his talent in Cobain's (and Courtney's) shadow.
I saw Soundgarden in concert with Faith No More and Voivod in the late 80s. I'd take any of those three over Nirvana any day of the week.
Iron Maiden is, IMHO, a Top 5 band. Iron Maiden took the pyrotechnics and over-the-top stage performances of KISS to a whole different stratosphere, and is among the top grossing live acts of all time. The majority of Americans have always undervalued Maiden. In Britain, Iron Maiden has had more #1 singles than any other performer aside from the Beatles. Even more than Ozzy has in his entire career, including his time with Sabbath. I'd put Maiden's Live After Death album down as the greatest live recording ever. When they were at their peek from '82 - '86, they couldn't be touched.
That list is a travashamockery. Suicidal Tendencies aren't on it. Danzig isn't on it. Hell, for better or worse, the pioneers of hair-metal glam-rock, Poison, aren't even on it!