My top 3 are:
3) Rowdy Roddy Piper, the ultimate heel against Hulk Hogan at the beginning of the WrestleMania era.
2) The Million Dollar Man Ted DiBiase, played the mean rich guy gimmick to perfection.
1) Mr. McMahon, the character that made Stone Cold an all-time great. Who didn't want to see SCSA beat the piss out of Mr. McMahon?