the knife bit in physco. Dont know if its music though but its mad anyway. and what about The Birds, though the music in it was also creepy, Jaws was pretty good too.
I've had a look around, and was starting to wonder if the orgasm connection was in my imagination.
I found one link, which doesn't outright say what it's about http://www.bbc.co.uk/dna/h2g2/alabaster/A709670 but hints a bit.
I'll keep looking anyway
I have a cd that has music from lots of horror movies, something like that could be quite useful. I've a feeling I lent it to my neighbour though so I might never see it again