You didn’t mention the band that did the greatest prog rock album ever.
http://www.youtube.com/watch?v=8-vXEJrU9i0&feature=related
If you like Tull, you’ll like Magma. Gypsy space prog rockers from France. They’re on YouTube.
Have you heard the recent "Aqualung Live" CD? It's a live recording of the entire Aqualung album, in order, done in a studio for with a small audience present, for broadcast .. in it, Ian jokes about how Aqualung was construed by reviewers as being a 'concept album', which it really wasn't. But that if they wanted a 'concept album', wait'll they hear THIS one! (meaning TAAB)
(just a little Ian'ism anecdote :)