For real, I was listening to some of the soundtracks to my most favorite movies/shows/games recently and was literally just plain aching. I mean, music manages to bring so much into a story, playing with your emotions almost subconsciously, connecting you to characters and situations more quickly and effectively than just showing them would have. Music can stick with you long after a story fades, or be the glue that makes a story stick.
For instance, years ago, I watched the movie Escaflowne:
(Yeah, don't believe the cover... it's not good. The show it's based on, however? Utterly fantastic.)
It's not that great of a movie. I mean, it's okay (it is really, really pretty to watch), but not the greatest (the English dub really ruined it for me too...). It was one of my first encounters with anime and while the story didn't impress me all that much, the music. Oh gosh, the music.
In particular, there was one song, sung by a minor character a few times through the course of the movie.
This. song. haunted. me.
I mean, for years.
(Related: Yoko Kanno is a genius among mortals. For real, check out her music - soundtracks especially.)
It was what actually made me watch the series years later when I found it on TVTropes, the sheer nostalgia of that one song.
I love this song so much that I actually bought the soundtrack, it being the second CD I ever really bought and the second soundtrack I purchased (the first CD and soundtrack being the Labyrinth soundtrack).
This song stuck with me much, much longer than the movie itself did. Or rather, the movie stuck with me because of that song.
Music is important to writers, regardless of medium or genre. I listen to music all the time when writing (mostly my ever-growing collection of soundtracks for their virtue of having no words that I could sing along to and thus write down). It taps into some deep, visceral part of us and humankind at large.
It can make something seem epic (really, try doing anything to the Pirates of the Caribbean soundtrack without feeling just a tiny bit awesome) or subtle or emotional or flippant with just a few notes. It can build or deflate tension.
It can also make or break a scene, as evidenced by those scenes/movies when the soundtrack is way too over-the-top for what's going on, or too underscored. But even then, the power of the music is demonstrated in the way that it does make or break the scene.
It makes me jealous. It really does. The closest we writers get is collections of music that we pick out for our novels (there are many folks who do this, especially around NaNo - making lists of music that relate to or inspire their story) or original music like what Maggie Stiefvater did for some of her books. But regardless, we lose that scene-by-scene synch that films get. Even if a reader listens to the music while reading the story, they lose the moment-by-moment impact and timing, since everyone reads at a different rate.
The closest we could get, I suppose, is an audio book with music, similar to some of Brian Jacques' Redwall books, where the song lyrics he writes are actually sung. But instead, there would be actual music throughout the whole thing, in the background. Which now I want to do. Like, start a company to do. The difficulty would be original music for even a fraction of what is often a several-hour epic read.