I've always been fascinated by Arnold Schwarzenegger's portrayal of the first Terminator in this movie. I've also always thought it to be a stroke of genius that James Cameron decided to cast him as this movie's chief villain at that point in time, being that he was known primarily for heroic roles like Conan in "Conan the Barbarian" (1982). But there's something about Schwarzenegger's minimal acting here that made the Terminator so terrifying (in my opinion, at least): his single-minded pursuit of his intended target, his intimidating physical presence, sparse dialogue, his cold-blooded and ruthless nature, his killing without any emotions whatsoever, and just the overall feeling that he just couldn't be stopped.
One thing I've always believed in movies is that sometimes the best good guys can sometimes play the best guys (like Schwarzenegger did in this movie). I really think he should have gotten at least a Golden Globe nomination for his frightening performance in this picture. I think it's extremely different from most portrayals of movie villainy before and since.
Anyone else believe that Arnold Schwarzenegger's first Terminator is the greatest movie villain ever?