The Sound of Music. Still a classic after all these years.
Grease could've been better, but is dragged down by some boring parts in the middle. The stage musical is more interesting because they have more numbers. Some of these numbers are just background music in the film.
But what about films that inspired musicals but were not musicals in the first place? For example, Waitress is not a musical movie but a comedy drama. But it now has a stage musical based on the film with music by Sara Bareilles, which has some great music. If they were to do an adaptation of that, is it just a remake of a musical that is a remake of a film? Or do they approach it like something like Les Mis, which has had many adaptations, some of which aren't musical at all, and then one of the actual stage musical? But that's based on source material. For Waitress, the original film is the source material.
Another musical film is God Help The Girl. which also has some great songs.
The song was used in an episode of Agents of SHIELD for Jemma Simmons, although it was this version not from the film but the stage musical:
I prefer the film version of the song with Emily Browning though. It's more catchy.