Well, a lot of my favorite movies are based on books, including my favorite movies of all time, so I'm going to go with movies with a comic book source here instead. And that gives me:
The Rocketeer (1991).
This movie didn't do well when it came out, and I've never figured out why because it's a great movie. The only thing I can think is with the period setting and the story line, this is a very old-fashioned movie. Maybe it just didn't jive with modern audiences, where people like me, who love older movies, period settings, and action -- well, this film was right up my alley. I mean it's set in the late 1930s, has Nazis and Hollywood actors and gangsters, a zeppelin, airplanes, Griffith Observatory, a wonderful Rondo Hatton look-alike, Howard Hughes, great costumes, a hero who flies, and a fabulous James Horner score. This is such a fun movie! The cast is perfect, the movie well-paced, funny dialog, the action thrilling. I love this movie.
Cliff: "How do I look?"
Peevy: "Like a hood ornament!"