2. Louise Fletcher
Wilbur Force, Jack Torrance, even the Joker; for all of Jack Nicholson's characters who weren't quite all there, it was the rather sane Randle Patrick McMurphy who found himself in an actual mental institution. In the classic tragedy that is One Flew Over The Cuckoo's Nest, rapist McMurphy has himself transferred for evaluation as a means of avoiding a hard and laborious prison sentence. Embodying the system that he is trying to subvert is the domineering figure of Nurse Mildred Ratched. More than just being the antagonist to Nicholson's (anti)hero, her obvious villainy comes from her upholding of the rules with an iron fist and all the psychotherapy equipment at her disposal. Although it's a film full of conflicts (remember while watching that you're cheering on a convicted rapist), it uses these to it's advantage; for all the tragedy of the film's climax, these only serve to bolster the resolution, and theme of the entire story; that of the human spirit. One of only three films to win all "Big Five" Oscars (Best Film, Screenplay, Director, Actor, and Actress), and which also co-starred several other famous Star Trek alumni (Christopher Lloyd and Voyager's Brad Dourif), One Flew Over The Cuckoo's Nest's Nurse Ratched is lauded by everyone from contemporary critics, modern audiences, and even Simon Pegg and Jessica Hynes' pop-culture saturated Spaced. Surely no-one was surprised when Fletcher was cast as the equally power hungry Kai Winn Adami.