Gotta be Charlie.
Keith himself said that if something happens to Charlie, the Stones are finished.
Plus he and Bill kept the Stones rolling, they weren't called the world's greatest rhythm section for no reason!
I think it's an easy tie...... Both drummers were lucky to be in bands with such consistent material that they were able to forge their own little niches and be creative in ways that stood out.....
For example, Mick Avory, I think, smokes both guys for pure ability, but since The Kinks were so dominated by one guy (Ray) as basically a vehicle for his songwriting, he wasn't able to forge much of an identity with his playing, which was always spot on and fantastic but he never got a "Day In The Life" or a "Rain" etc etc to show off on, nor did The Kinks have so much of a unified/identifiable SOUND ala the Stones for the drums to be such an integral part of.