What a list! Great read.

Some filmmakers leverage symphony to set the mood, others prefer to just insert appropriate background music. I know its a pet peeve of Martin Scorsese's not to use much in the way of symphony, he feels that it does too much to lead the audience hampering the viewers ability to take their own emotional voyage. Others absolutely depend on it to shape the emotions of a scene, while some films are primarily about music themselves. Point being that film and music are kind of like chocolate and peanut butter.

So take a film like Hitchcock's Phycho which is obviously scored orchestrally to help add emotion in scenes that needed it at the time because a little chocolate syrup in a bathtub was considered gratuitous. Contrast it to the music Scorsese selects for films like Goodfellas or The Departed, and you can really hear a difference in the style and delivery, yet music is a critical component to those films. American Graffiti is another great film soundtrack entirely made up of appropriate tunes from that era. I remember seeing Lucas in an interview saying he preferred that approach, but just did not know how to apply it to Star Wars, then John Williams comes along.

Then you have soundtracks that are as much the films themselves, West Side Story is probably the best example of this.

Fantastic list, especially love the Trainspotting and Pump Up the Volume soundtracks.