One of my favorite movies — if I ever make up a "Top 50," it'll be on it — is the 1975 Dog Day Afternoon. It was directed by Sidney Lumet and it starred Al Pacino, back when Al Pacino didn't sound like an impressionist doing Al Pacino. When I started going with my lovely friend Amber, she asked me to show her some of the movies I liked and this was among the first we watched together. It immediately became a favorite of hers, as well.
The fine blog of Mr. Paul Harris just led me to a fine, long article by Daniel Edward Rosen about the movie and about the true crime story on which it was based. If you're a fan of this movie, let this link lead you to that article.