i'm assuming from your picks that you meant male vocalists, yes?

frank fontaine
nat king cole
neil diamond
pavoratti
bing crosby
the guy who played christ in the video of jesus christ superstar.
a tenor i once heard on a black and white late night tv show who sang waltzing matilda (never knew his name and never heard it again, so sorry, but it was incredible)
andy williams
harry bellafonte
barry white

runners up: mel torme, michael jackson, meatloaf

there are others as well, but most of those that i'm thinking of were parts of groups, so i didnt include any of them.

K.