Frankie Valli, Nat King Cole, Al Martino, Mel Torme, Wayne Newton (I'll probably get some comment on that one) and the Man, Bobby Darin all are at the top of my list as great singers.
I've always liked listening to a guy who could sing really well with a big band.
I saw Wayne Newton, when he was only about 15 or 16, at the Steel Pier in Atlantic City. I'll always remember that show cause he worked so well with the band. I commented that he will be a big star and not all of my friends shared that opinion. I saw Bobby Darin several times and he was the same way. He was and still is, by far, my favorite.
( besides he married Sandra Dee and she was somethin'!!)
The very best voice, though, I've got to say Jerry Vale.