Monsieur Verdoux

A suave but cynical man (Charles Chaplin) supports his family by marrying and murdering rich women for their money, but the job has some occupational hazards.

This film is brilliant, because it is not just entertaining, but also has a strong message. On the surface, it is a man who marries women and kills them in order to get their money. This in itself makes for a good film (and is somewhat risqué for the 1940s). But then, it is also a metaphor for society -- capitalism, imperialism, war... Chaplin takes on the Great Depression and the war industry.

Most people know Chaplin for his silent films and tramp character, but he really became a strong filmmaker in his later years. This film, along with "Great Dictator" and "King in New York" are among his best works. It is a shame that for whatever reason he is not remembered for the second half of his career.