No. 2: "Jaws"
The music is instantly recognizable, even if you've never seen the movie. The alternating E and F notes are universally recognized as meaning that danger is near.
Whether or not you've seen "Jaws," you recognize the music and what it means.
It was the movie that wrecked swimming during the summer of 1975. Whether it was in the ocean or the local swimming hole, something HAD to be out there, and if a piece of seaweed touched your foot, you could run on top of the water to get back to the shore.
Jaws was the movie that created the summer blockbuster -- and the career of a then-unknown filmmaker named Steven Spielberg. The movie also had the odious honor of spawning so many reprehensible sequels, but that wasn't Spielberg's fault -- that was the studio trying to squeeze every penny they could out of the franchise.