Walt, Eisner (when Wells was still alive), and believe or not Iger.
I was down on Iger for a long time, but i believe he had a good mixture of allowing creativity and being a corporate CEO.
Walt had an idea for Disney World, but wasnt around to execute on it. so its probably fair to include Roy in this conversation as well.
Eisney doesnt get the credit he deserves for what WDW is today.
One of the major issues that Disney suffers today, is that there is no longer a Disney in the company to help steer the ship. Walt's nephew, Roy, lead a charge to oust 2 Disney CEO's that he believed had lost their way. There is no one left to do that.