I had to think about this, probably more than I had to think about the Bill Murray poll. The obvious first choices for me were Captain Oveur or Dr. Rumack, but after careful consideration I had to go with Johnny. He delivers nothing but one liners throughout the greater part, if not all, of the movie. Each one of them is hysterical. I think he's the most underrated of the group and has the best lines.
Johnny - "Where did you get that dress, it's awful, and those shoes and that coat, jeeeeez!"