I've always loved that song, and until I heard the news earlier I never realised Noel was Rex Harrisons son.

Ah, dear Rex

Yes, Windmills of Your Mind is one of those songs which is even more memorable than the original film as it sticks in your mind.

There's another song which was first used in a film and the song became far far more famous than the film itself. That's Unchained Melody. The reason it's called Unchained Melody is because it was in the 1955 film Unchained which is set in a prison. I've never seen the film and probably very few of us have. This is the clip from that film. It's sung by Todd Duncan and the famous version by the Righteous Brothers was released years later.

Loved the song too, and didnt know either he was Rex Harrisons son. 
R.I.P x