Pink Floyd, whom I would also rate above Yes and the Moody Blues, only released 14 studio albums. Two of those were with Syd Barrett, one (Ummagumma) was a collection of solo pieces packaged together with a live disc. One (The Final Cut) was made without founder-member Richard Wright.
The "main sequence" of PF albums, consisted of Atom Heart Mother (an OK record), Meddle (brilliant), the Obscured by Clouds soundtrack (good but not essential), Dark Side, Wish You Were Here, Animals, and The Wall. Seven albums.
IMO, The Final Cut is a Waters solo LP that happens to have Gilmour and Mason playing on it, not a real PF album.
So PF were great, but their essential catalog is not a huge one, nor was their total output.
Source:
http://en.wikipedia.org/wiki/Pink_Floyd_discography