This thread is pretty much asking for alot of personal opinions that people believe are "facts" this is like the horn to signal the Stan World Hunger Games.
Well...
I think Sharon den Adel has the best voice to ever be placed on a woman.
I think Joey Jordison is THE most skilled of all drummers.
Those 2 are really the only people I'd confidently put on a all-time pedestal.
Hmm.. interesting.
I believe that title belongs to Mike Portnoy, James Owen Sullivan, or Matthew Helders. Mike Portnoy mainly because he has the experience and is diverse. He can go from metal to progressive in the snap of a finger. I think someone that is skilled needs to have that amount of experience. That's just me though.
I really wouldn't know considering I haven't really listened to much, besides the classics, past the 90's. But I can say if anyone is going to be naming names from this millennium you have to say Kanye.