My fourth favorite Woody Allen film is Manhattan. It is very similar to his other relationship films, namely Annie Hall and Hannah and Her Sisters. What sets it apart is its wonderful black and white cinematography and fantastic score, consisting of George Gershwin's music. The best and most famous shot in the whole film is this one, which would be great just as a still photo.
Allen's philosophy on love and relationships is very cynical, so many of his movies are rather depressing. But they are insightful, and often highly funny. A good line for the film is uttered by Allen's character named Issac, speaking to his ex-wife:
My analyst warned me about you. But you were so beautiful I hired a new analyst.