People always talk about Hannibal Lecter being the favorite of all horror based fictional psychiatrists. "Feh", I say. The best horror psychiatrist has to be Dr. Sam Loomis, best known for being the child psychiatrist of Michael meyers of Halloween fame. With his overcoat and his wounded howl, Loomis was the shiz-nit. Hell, he got to shoot at Meyers on occasion. That was pretty bad-ass.
I also loved Pleasence as the president in Escape from New York ( shouting, "Top Dog! A Number One!" as he gunned down Isaac Hayes), the priest in the overlooked Prince of Darkness and the evil spy in Fantastic Voyage who gets eaten by a white blood cell.