Very interesting article in SPIN about 40 movie soundtracks that have changed the way music was thought by bands, especiallly by alternative bands, groups that could expand on a music heard in a movie without losing the interest of its demographic.
For instance, no doubts that the soundtrack of "Forbidden Planet" has led many youngsters to electronic music (it's actually interesting to notice this love of pure, raw, weird electronic sounds is actualy making a huge come back with the development of the Eurorack scenes and the availability of many electronic modules these days).
There are also very few doubts that the cinematic music of Morricone has impress bands like 80's sweeties The Pet Shop Boys, and closer to us Goldfrapp and somehow led to Godspeed! You Black Emperor.
Or that Clockwork Orange paved the way for Kraftwerk with its cold and icey use of Moog synthesizers. And what about Eraserhead who can be seen as Grand Father of Gothic music, along with Danny Elfman and his haunting themes for Tim Burton's movies?
If there ever was a movie that will launch a music style to the higher places, it must then be "Saturday Night Fever" who made disco...