Do you know of any ROCK singer who was a heavy smoker but still managed to keep their voice after many years?

Lemmy from Motörhead

I'm pretty sure Roger Waters was a heavy smoker, but his voice really hasn't deteriorated all that much (if at all) since his Pink Floyd days. I saw him on his tour for "The Wall" four years ago and he sounded almost exactly like he did in 1979-1981.

John Lennon and David Bowie

Freddie Mercury smoked, although I cannot say if it was heavily or not.