The DVD release date of King Kong gets nearer, and while we're waiting, I'll note that perhaps the movie's greatest contribution to the art of cinema was not its special effects (groundbreaking though they were, they didn't immediately inspire a lot of similar effects) but its re-popularization of music in movies.
When talking pictures came in, perhaps the worst artistic decision made by most producers -- not only in America, but worldwide -- was to release films with no background scores. Most early sound movies have music over the opening titles, and source music (like the record playing "I'm Forever Blowing Bubbles" in The Public Enemy), and maybe the occasional instrumentalist on the soundtrack (like the ensemble in Boudu Saved From Drowning), but no specially-composed, fully-orchestrated music accompanying the action.
The thinking was, I take it, that the purpose of music was to accompany scenes that didn't have any sound; if you have sound, you don't need music. It was a misguided notion. Many early sound films are severely hobbled by the lack of music; Frankenstein and Dr. Jekyll and Mr. Hyde are two great movies that really cry out for music at key points.
Max Steiner and his big score for King Kong helped to change all that and really show how much a talking picture could benefit from a new, specially-composed score. Not that there hadn't been any talking pictures with musical scores -- Lubitsch's Trouble in Paradise uses a lot of background music, composed in a style very similar to a score that might have accompanied a silent film -- but they were one-offs and flukes. It was Steiner, I think, who proved that talking pictures needed music as much as silent pictures did. From that point on, most dramatic movies had musical scores. Comedies still often went unscored (Bringing Up Baby has no musical score, nor does the serio-comic The Rules of the Game), but by the '40s, every movie had a composer. Since then, there have been only three types of movies without background music: movies that make a special effect out of the absence of a score (Robert Wise's The Set-Up; all but the last minute of The Asphalt Jungle); movies that use pop songs instead of a score (Goodfellas); and post-1961 movies by Ingmar Bergman, whose dislike of musical scores is just one of the many things that annoy me about him.
I'm not even a huge fan of Steiner's music -- like Alfred Newman, he was a fine musician but a very unsubtle composer. But Steiner, more than anyone, re-established the profession of film composition at a time when most producers seemed to think it wasn't necessary. So to a certain extent we can thank Mr. Steiner, and Mr. Kong, for Korngold and Auric and Raksin and Delerue and various people named Bernstein and several hundred people named Newman.