Heenan will always be my favorite.
Had storyline credibility, being a wrestler himself.
Was funny and entertaining.
Was an excellent mouthpiece for guys who couldn't talk.
Took better bumps in the match than some of the guys he managed.
Bobby was also the third in command of the WWF at one point, until I think it was George Scott who started a thinly-veiled petition to do away with the position.
Sherri possessed many of the above qualities, and her work with Savage was hilarious. As a bonus, she always looked very edible in those outfits she wore. Larry Zyszko was a lucky guy.
Albano & Blassie are, of course, excellent picks.
Add Fuji to the list. He was great with Muraco, the Moondogs, and Demolition later on.