6. Axl Rose
Slash still remembers the first time he heard Axl Rose's singing voice. It was on a low-fidelity cassette tape that he heard shortly before joining Guns N' Roses. "His squeal was so high-pitched that I thought it might be a technical flaw on the tape," he wrote in his memoir, Slash. "It sounded like the squeak that a cassette makes just before the tape snaps – except it was in key." When Slash realized the superhuman voice was actually legit, he knew he had found his frontman. Axl is an extremely difficult man to work with, but few other men on earth could sing material like "You Could Be Mine." Maybe that's why Velvet Revolver has had such a hard time finding a new singer.