Thelonious Monk - Monk's Dream
Monk's playing style was really ahead of his time, well ahead of any time for that matter. It's also interesting noting clear Ellington influences, despite the fact that his playing style is so different. The same goes for Mingus too. In many ways, it seems like the bepop style that Monk and Mingus worked off of was the result of taking Ellington's ideas and bringing them to a small group, seeing what new ideas would come out of the mix, like scientists putting a different enzyme into the same substrate (I think).
My favorite track: Body and Soul