"A small town doctor learns that the population of his community is being replaced by emotionless alien duplicates."
http://www.imdb.com/title/tt0049366/The original version of this classic tale is either the best version or as good as the 1978 Donald Sutherland remake. It's an intelligent and creepy thriller that sees Kevin McCarthy driven mental by an invasion of alien pod people that duplicate the folk around him leaving everything the same but different! Hugely watchable, classy horror history.
5/5 quality 1/5 for scares
Watch the whole film here! http://www.youtube.com/watch?v=ZAY37Zd6mIE