Okay, here's my list!
Rob Halford (Judas Priest)
Ronnie Van Zant (Lynyrd Skynyrd)
Eddie Vedder (Pearl Jam)
Bon Scott (AC/DC)
ZP Theart (DragonForce)
Chester Bennington & Mike Shinoda (Linkin Park)
James Hetfield (Metallica)
Ozzy Osbourne (Black Sabbath, solo)
David Draiman (Disturbed)
Rick Astley
Till Lindemann (Rammstein)
Some these are sure to raise a few eyebrows so I'll explain as effectively as I can. ZP Theart may be part of the one of the biggest comedy relief acts on the Internet but his ability to sing at such a high range and match the beat of the song is simply admirable.
James Hetfield has a delightfully maniacal, snarling bark. He sounds like he's having a good time when in full swing, which is scary considering the subject of thrash metal.
Chester and Mike...okay, I admit that's two vocalists but you can't have one without the other. I love their ability to seamlessly alternate parts and sing in unison. Also, it's pleasing to know that the rapping is left to the guy who isn't white.
Don't "OMFGLOL" at Rick Astley. He has an amazingly deep, soothing voice for a white guy and makes his otherwise cheesy-at-best viral hit something to behold.