Bruce ****inson - Iron Maiden
Maynard James Keenan - Tool
Charlotte Wessels - Delain

Because nobody has mentioned them so far:

Max Cavalera-Sepultura and Soulfly.
Warrel Dane-Nevermore.
Jens Kidman-Mehuggah.

If I may opine on some of the previous choices here, Dickinson and Akerfeldt are getting way too much credit. Dickinson is technically proficient but pretty lacking in raw power or emotional content (possibly the main thing that sets Maiden a notch below Judas Priest). Akerfeldt seems only remarkable due to the fact that he sings clean vocals in addition to death growls, and while his clean voice sounds very nice his tone is just too plain and "gentle" to really be compelling.

Off the top of my head, I'd rank these guys as among the best:

* Halford (duh)
* Quorthon (definitely for emotional content above anything else)
* Dio

Oh, and an honorable mention to Layne Staley of Alice in Chains, as AiC aren't exactly metal but Layne crushes all three of the above guys talent-wise. :)

Why do you think Layne Staley has more talent than the first three you mentioned?

Staley sang in a very expressive, powerful and emotionally honest way. He was a guy plagued with drug addiction and slowly dying from it throughout the band's career, and his vocals convey that inner torment and mental and emotional chaos with a disturbing level of realism. His lyrics are not only clever but also a great window into his psychology, and you can find all kinds of introspection, soul-searching and 'cries for help' in them. Even though few of us are drug addicts, it's very easy to relate to Layne because his emotions are so very real and well-articulated. Add to that a great sense of melody, and I think you have a vocalist of the highest caliber in Layne.

I certainly can`t argue with that assessment. I always thought he was a great vocalist, despite the fact that I preferred other grunge bands of the era.

Layne is easily one of my favorite, and.. yes, probably one of the best. But can you really call him a metal vocalist? I'm going with no.. AiC has some elements of Metal in their music.. but I wouldn't ever call them a metal band.

Eh as for me..

Chuck Billy
Ronnie James Dio
and..

hmmm..

Rob Halford maybe?

idk, I don't have much time to think about it. So I should probably have waited to post this! But nope.

1. Russell Allen
2. Christian Avelstam
3. Hansi Kursch

Also King Diamond is in his own category...

Russel Allen, definitely.

Maynard James Keenan from Tool and Bruce D1ckenson. I'm kinda biased towards prog, as you can see.

This might be a bit of a stretch for the metal thread, but Robert Plant has always been one of the most spot on singers imo.