Stuartk, in the sense you're talking about it's a bit like listening to classical music. I am now listening to a Ravel string quartet. Ravel incorporated jazz into his later classical pieces. He came to America to hear jazz. He and Debussy had a heavy influence on modern classical music. Bartok, one of my favorite composers, said he was most influenced by Debussy.
One of the problems I have with some of the jazz you're talking about is their lack of melody. They are often driven by rhythm, and there is a lack of what I would call a strong melodic hook. Perhaps I have not attuned my ear to their melodies. It took me years with many modern composers, like Shostakovitch whose piano concerto I'm now listening to. His melodies are a bit dissonent but they are there.
I think a lot of the older jazz musicians based their music on themes that were standards, like "My Favorite Things." Then the melody is not a problem. Of course, Coltrane comes up with some heavy-duty melodies in "A Love Supreme" and Miles Davis in "Kinda Blue." A good melody is very hard to find, though, and I think some intricate jazz pieces eschew a strong melody and base their music on structural intricacy and rhythmic drive. Those are more difficult for me to listen to.
