As you know, I don't generally bite on challenges. But if I did, this would have to be subdivided as follows:

1) Favourite musicals. Already done, here: https://medium.com/fan-fare/my-twelve-favourite-musicals-2cd0536e18a7

2) Favourite film composers. A new article already written coming at some point over the next few weeks. Watch this space.

3) Favourite film scores. All but impossible to list, but here's one of my all-time favourites: https://medium.com/the-riff/my-favourite-john-williams-score-e-t-the-extra-terrestrial-9eea044f61b8

4) Favourite musical biopics. I'd include pop biopics such as The Buddy Holly Story, What's Love Got to Do with It, Control, Ray, La Vie En Rose, Sid and Nancy, Walk the Line, and some classical composer biopics like Amadeus. Admittedly things get a little muddy with Rocketman, as that's a musical rather than a musical biopic, to my mind. Whereas something like Bohemian Rhapsody (not a great film really, although I love Queen) is a biopic.

5) Favourite films making great uses of classical music: Death in Venice, Platoon, 2001: A Space Odyssey, Barry Lyndon, A Clockwork Orange (a lot of Kubrick, actually), etc.

6) Favourite pop soundtracks: The Graduate, Saturday Night Fever, Pulp Fiction, etc. Here's a piece I did on Top Gun, if you're interested: https://medium.com/the-riff/top-gun-soundtrack-revisited-42f0d27e58e5

7) Favourite concert films: Here's what I consider the Citizen Kane of concert films: https://medium.com/the-riff/stop-making-sense-the-citizen-kane-of-concert-movies-d36beee50446

8) Finally, just because I love Pet Shop Boys so much, here's a piece I did on It Couldn't Happen Here. It's not a very good film, but the music is snyth pop heaven: https://medium.com/the-riff/pet-shop-boys-it-couldnt-happen-here-498006c44a74

Anyway, I won't be biting on this prompt, but this inordinately lengthy comment gives you a reason as to why. My well-ordered mind simply finds it too broad. :)