Best Male Singers of the 20th Century

There is an interesting current discussion about the best female vocalists on CD. I have my own ideas about the best male singers (any category) of the 20th Century, but would like to hear other opinions.
Well, I am sure someone will mention Belafonte, and of course there is Nat King Cole (the DCC reissues are awesome) In the "sub class" of Best singer/songwriter, I'd vote for Jacques Brel also.
Mel Torme. Mel was at least the greatest male jazz singer (with only Ella and Sarah Vaughn contending for best jazz singer overall.) Mel was also a terrific writer (Chestnuts roasting on an open fire) and arranger.
I like Louis Armstrong for Jazz, Bing Crosby for crooners, Ian Gillan for Rock, and Bob Dylan as the "Is he singin' or whinin' catagory" nominee.
Well, since I started this thread I suppose I should participate. Among the "greats" I would include, by category: Opera: Feyodor Chaliapin (Russian basso), Lauritz Melchior, Paul Roberson, Enrico Caruso, Ezio Pinza, Richard Tucker, Jon Vickers, Luciano Pavarotti, Placido Domingo, etc. (there are probably another dozen that deserve to be on this list). Popular: Frank Sinatra (absolutely no doubt on this one - not one of the "spectacular" voices, but without question one of the 2-3 best song stylists), Mario Lanza, Elvis Presley, Elton John, Stevie Wonder. Jazz: Mel Torme, Joe Williams, Jimmy Rushing, Bobby McFerrin, Al Jarreau, Jon Hendricks, and my personal favorite, Mark Murphy (if you don't know his work, and like vocal jazz, you have missed one of the true greats). Blues: Robert Johnson, Big Bill Broonzy, Blind Willy McTell, BB King, Albert King, Luther Allison, etc. Rock: There are a few I like, but I'm not sure any of them belong in the "best singers" category. My short list might include David Clayton Thomas, John Fogerty, Jim Morrison, etc., but rock singing is more a matter of style, I think, than "voice" (think of Joe Cocker, for example). Folk: Paul Simon, Glen Yarborough, Woody Guthrie, Pete Seeger, Bob Dylan (I personally never liked his singing, but as hugely popular as he was, he probably deserves to be on this list). This list should prime the pump - now let's hear from others and see who they include!