As I stated in my original post, what I posted was not a "list," but simply the current highest-rated (based on a modified mean) 50 albums on a particular album-rating database, which I thought might be helpful for anyone interested in some top-notch prog albums that they perhaps had not heard of. I emphasize the word "current," because it changes all of the time -- there have been at least a 20 top rated albums on that site since I discovered it a number of years ago. The criteria to participate (at least, the last time I checked) is to be able to provide ratings for at least 2000 albums right off the bat, and then be able to contibute several per week thereafter -- thereby making it a much more valuable resource than other similar sites available on the internet, which are simply places where anybody can rate anything. The site administrators use responsible statistical models to develop their averages, so that albums with few reviews won't get rated disproportionately high or low, if those relatively few reviews bunch at the top or bottom of the ratings scale. I don't know why you'd discount the jazz albums in the ratings, since the purpose of the site is "exploratory, creative and original music of the past, present and future," and jazz certainly qualifies. They have rated several thousand jazz albums. If you want to throw out the jazz albums, however, then the more prog-related albums that would replace the five slots that the jazz albums had taken up, would be:
46. Osana -- Palepoli
47. Univers Zero -- UZED
48. Area -- Crac
49. Soft Machine -- Third
50. Le Orme -- Felona e Serona