Since Duke has been a guiding light to the idea, let's start with his live version of 'Take the A Train' in 1957. Though the studio version is excellent, and a must-listen in itself, this particular live version has such verve and meaning -- I particularly love how Harry Carney's baritone sax comes through, almost like he's leading from the bottom. It also gives a snapshot of the Ellington band on an average night in the late 50s; an era when it was difficult to keep a Big Band on the road or together at all. The commitment of the musicians shines through.