He's near the top for me, too. Others:
Stephen Marriott (Small Faces, Humble Pie, etc)
Phil Lynott (Thin Lizzy)
John Wetton (un, lot'sa Prog outfits)
Steve Perry (Jourbey bashers among ye: this man had Big Voice)
Skip James
Howlin' Wolf
Elmore James
Marvin Gaye
Curtis Mayfield
Roger Daltrey
Paul Rodgers
Frank Sinatra (Sr)
Hank Williams (Sr)
George Jones
Luciano Pavarotti
Samuel Ramey
Dietrich Fischer-Dieskau
Let's stop there.
Nobody mentioned Tom Waits yet...
My favourite male vocalist is Dietrich Fischer-Dieskau.
In no order:
David Bowie
Tom Waits
Beck
Alex Kapranos (Franz Ferdinand)
Damon Albarn (Blur/Gorillaz)
Chino Moreno (Deftones)
Josh Homme (Queens of the Stone Age)
David Byrne (Talking Heads)
Sting (The Police)
Geddy Lee (Rush)
Colin Hay (Men at Work)
Dave Grohl (Foo Fighters)
Joe Strummer and Mick Jones (The Clash)
Roger Daltrey (The Who)