If I had to chose one from all time, it would probably be the theme to Starwars. Not sure if they made a soundtrack of that, but that is one that comes to mind.
The Sound of Music would be another one, and the Wizard of oz.
I'm sure there a lot of Disney films that would give these a run for their money. But, since I have not seen any in a while, I would have to think about it. Maybe Fantasia.
Maybe Hello Dolly. Saturday night Fever, and Grease.
I recently saw the new release of "Hairspray" with John Travolta. It was a very good movie, and had some great music.
Some of it was even kind of funny.