I will not take anything away from Heenan, he is the man.
However, I went with James E. Cornette. If there was a legitimate second best, in managers as well as wrestling minds. It's Cornette. He is the man that would make you want to just kick his ass. And that Tennis racket always got involved in his matches. In addition, when you're managing the most underrated tag team in history (the Midnight Express, who made a SCIENCE out of Double Team wrestling)...
Also, where's Skandor Aackbar (sp?)