AFI's 100 Years...100 Songs list was really lacking in the original scores department and it didn't even include "Uncle F*cker" from "South Park: Bigger, Longer & Uncut". :)
I realize that a lot of the famous scores probably didn't get much consideration because there are no lyrics, but a great score can evoke so much emotion from us without us even realizing it.
Composers like John Williams ("Star Wars", "Jaws", "Raiders of the Lost Ark", "Catch Me If You Can", "Superman") Danny Elfman ("Batman", "Pee Wee's Big Adventure", "Beetlejuice") and Thomas Newman ("American Beauty", "The Shawshank Redemption", "The Road to Perdition") bring so much to a movie.
Admit it... you're humming the "Star Wars" theme right now, aren't you?