Well, as the thread has shown, first you have to have the argument about what is, or isn’t metal – bands like Sabbath, Deep Purple and Zep have consistently denied the label over the years, for example. And then what about bands where there’s a “metal” element, but the overall sound is more or different, so Faith No More, NIN, Jane’s Addiction, for example?
And once you resolve that, how are you defining ‘best’? Most successful? Most awards? Best distillation of influences up to that point, or most innovative / pushing things forward?
Maybe I’m over-thinking it?
My choice would be Jane’s Addiction – Nothing Shocking. Maybe not the most listened to, or the most listenable, or the most hard rockin’, but for its influence on what came after, and in particular for opening ears to other ways to use “metal” than in what was becoming, at that point in time an increasingly one dimensional genre.