There is a really interesting list of the best time film soundtracks at Movie Mail, with some I would never have considered:
10. Ivan the Terrible
9. On her Majesty's Secret Service
8. The Dam Busters
7. Deep Red
6. Le Mepris
5. Jaws
4. Faccia a Faccia
3. Woman of the Dunes
2. Taxi Driver
1. The Draughtsman's Contract
If you want to look at the list with arguments for each entry and sound clips, go to:
Ten of the Best Soundtracks, with clips | Movie Mail UK