Sinatra (I don't know that his "voice" was that sensational, but his style made it great.
Well put. There were literally dozens of his contemporaries with better voices (and several Italian-Americans, like Jerry Vale and Jimmy Roselli), but Frank's showmanship and swagger put them all to shame.
So to me, best singers and best voices are really two entirely different animals. So while Sinatra, to me, is the greatest "singer" of all time, for best voice I gotta go with Elvis Presley. Who else had the range to sing Country, Gospel, Pop and Rock and Roll?
(One Night With You) to, like you say "country-ish" (top of my head U.S. Male but I know there's more); to the sweet love songs like (It's Now or Never, Surrender); And, gospel, with songs like I'm Saved or one of my favorite spirituals by EP, "I Believe". Anyway, I say these particulars tunes off the top of my head. I know there are more and even better ones that I'm not thinking of. Definitely Elvis remains my all-time favorite. 
