best rock voices

Robert Pollard put out a solo recording, and toured in support of it. Haven't heard anything about the other band members.

Other great rock voices:
Kristin Hersh (Throwing Muses)
Kings X - in concert, they harmonize like Queen
Phil Lynott (Thin Lizzy)

Cornell can sing, but nothing 1000 others don't sound like, the most unique and have never been rivaled :

Maynard James Keenan,
Perry Farell,
Robert plant,
Bowie,
Beck,
David Gilmore,
Hendrix,
Dave mustaine

And of course
Peter Steele

Lots of great voices listed so far. But, if I could wake up tomorrow and sing like anyone I wished to, it would be the late, great, and under appreciated Chris Whitley. Man, if there ever was a more expressive and soulful anglo singer than Chris, I've never heard them. Rest in peace Chris.

AL COOPER..

Cornell can sing, but nothing 1000 others don't sound like

True enough, but they're imitating HIM.