Honestly, I could write a list a mile long of male vocalists I find completely astounding. Most of which would probably come from the 70's, but that's cool.
As a musician I've often overlooked what goes into vocals and the human quality they truly bring to a band, but I'm glad I've pretty much gotten over that.
I would have to say Maynard as one of them, Garm is also an excellent example. There really is to many to list, you need to break it down into genres. Like comparing some pop singer say michael Jackson and Quorthon doesnt really work.