@Zetetic11235,
There are a number of great books about the aesthetics of music, some of which I own and have read (loosely, not studied in detail). A simple one (with a western classical bias) is "Music, the Brain, and Ecstasy". Another great one by an actual philosopher is "Aesthetics of Music" by Roger Scruton.
What I find interesting is that very little music actually imitates nature. Natural sounds, incl birdcalls, are atonal.
So music hits us very viscerally, but it's an abstract art!! It's non-representational (except with respect to lyrics). Anyone who has difficulty appreciating a Kandinsky or a Rothko or a Pollack painting should think about music -- it's also abstract and it also strikes home, somehow.
I have very broad music tastes. I love classical and opera, I love world music esp from Africa, and I'm currently listening to a lot of Radiohead, Coldplay, and some lesser known Indie groups like Elbow, Shearwater, Museum Pieces, et al. Music moves through conflict and resolution, through momentum, through poignancy. And these are difficult to quantify. Add on top lyrical geniuses like Bob Dylan, Tom Waits, Bruce Springstein, or even Thom Yorke, and you get a real synergy between poetry and abstraction.