I liked Joni Mitchell's stuff from the early 70's, but it was when she teamed up with a set of jazz mega-stars that she really caught my ear. Particularly the live "Shadows & Light" stuff -
you can see/hear a sample here. Jaco is perhaps the best electric bassist ever, Pat Metheny is a tremendous guitarist and composer with a deeply lyrical style, Lyle Mays has been Metheny's co-conspirator for 30 years now, and Michael Brecker (recently died of Leukemia) was a tremendous voice on the tenor sax for many years ... Joni Mitchell is essentially a folk singer, but always saw her voice as more than just a channel for the words ...
Speaking of YouTube,
here is an interesting find that shows some music I like - and from SNL, no less. Of course, this is from '79 when they would actually do daring stuff. The sound quality is pretty crappy, but there is some very complex structural stuff going on there - all in the Harmolodic form.
On the subject of 'instrumental' music, if you refer to it as such that is already bad since it implies that there is something 'missing'. Because I firmly believe that it isn't just possible to convey information and messages through music, but that they are more real and deep than those pt across through most lyrics ... but if you can't appreciate it then I think one of two things is going on - either you don't have an ear for music, or the people playing what you've heard lack the ability to put across a message musically.
And I don't mean that as elitist or insulting - most musicians are trained in the 'rock solo' method which is very impressive but limited, and most listeners learn about music through listening to popular songs, which have an extremely limited palette which is subservient to the words of the singer. It is very much like watching War of the Worlds on TV compared to listening to a radio show. Or watching a movie compared to reading a book.