Hmm, TD did quite well for themselves, regardless who was in there with Edgar, in the film soundtrack market. Even if they did slide into the 'new age' catagory, as many aging prog people did, the ensemble was still a going concern all the way up to Froese's illness and passing. They cranked out quite a number of titles.
My nomination is a trio that should be near and dear to all of our hearts, as the focal point of the band is a tour-de-force bassist, but the other two guys(of the original line-up)certainly held their own. Unfortunately, there's not a whole lot of archival video; hell, they even got sampled by the Beastie Boys...ladies and gentlemen, Back Door(with Colin Hodgkinson)...
keep in mind, this is from 1972
CH solo in 1975
a latter-day reunion; the sax player and drummer have since died
granted, this is not mainstream pop appeal stuff; the only other people I've encountered that were into this band were fusion, Zappa, Ornette Coleman and Henry Cow fans.