All this talk about jazz reminded me how much I loved this album:
Fourth (1971) by Soft Machine
Soft Machine is one of my favorite prog rock bands of all time (ranking with Henry Cow, Spirit, and Gentle Giant).
Fourth, however, is much more jazz-oriented than their three previous albums. Even though this release dropped most (if not all) of the progressive rock elements that we all attribute with the Canterbury scene, this is still a fantastic jazz album.