One of the greatest pleasures in listening to jazz is found in the walking bass. Its role is to provide the connection between the harmony and the rhythm, both of which are usually very complex. But in the hands of a master, when every note is chosen and played with knowledge and care, it creates a streamlined logic and sense of resolved expectation that is largely responsible for what Ellington called "the feeling of jazz". One such master was Ray Brown, who was the kind of bassist who elevated every date (live or recorded) that he played on. I had a teacher once who said that what he'd been enjoying the most in his personal listening over the previous year or so was "anything with Ray Brown". Here's an excellent clip of him playing Luiz Bonfa's "Black Orpheus": (http://www.youtube.com/watch?v=6bJu2owDM2E).