It would have to be either Benny Greb or Carter Beauford. I went to a Benny Greb drum clinic and he was really funny. He just seems like a fun person to be around and his drumming is amazing. And I really dig Carter Beauford's style. Its a tough choice between the two for me.
To be taught time keeping and groove concepts by Ndugu Chanceller or Steve Gadd would be great.
I would also love to learn from Chester Thompson on how he approaches different musical situations. Maybe we could sit for an hour and discuss the music business too.
There's so much to be learned that doesn't require a drum throne.
Honestly, I couldn't pick one or a couple. I'd have to say any drummer that I've heard and liked, even if Drummer X,Y and Z played the same (or similar) thing, perhaps they each had a different approach about it.
Mike Portnoy, Mike Mangini, Ringo (yes, Ringo), or if he was alive, Bonzo.
Portnoy's always been my idol. Mangini is just a beast. Ringo was around to really see music develope and created some of the biggest changes to drumming I've ever heard. And John Bonham is John Bonham.