Brian Johnson Ac/DC
http://www.youtube.com/watch?v=POf7BC_o9UU&feature=related
Dio (this one will blow your effing mind!)
http://www.youtube.com/watch?v=vxLCzOWllH8
Dave King (flogging molly)
http://www.youtube.com/watch?v=2E4_Yt7guGQ&feature=related
And here's a sad one, a song by a guy whose voice had changed, career was in the toilet, but could still sing the hell out of a song. Frankie Lymon