9. Chris Cornell
Chris Cornell's voice packs so much power that over the past 20 years superstar collaborators have lined up to work with him – everyone from members of Rage Against The Machine to Santana, Pearl Jam and even hip-hop producer Timbaland. The latter move dismayed Cornell's longtime rock fans, but they were overjoyed last year when he reunited with Soundgarden. They're in the studio right now cutting a new album, with many more concerts likely to come in the near future.