Arbitrarily limiting the definition of "prog" to mean music recorded
between, say, 1969 and 1977, but not doing anything to separate out any
subgenres because the hairsplitting just gets too intense even for me:

1. ROCK BOTTOM  -- Robert Wyatt
2. HATFIELD AND THE NORTH -- Hatfield and the North
3. VOLUME II -- The Soft Machine
4. TAKING TIGER MOUNTAIN BY STRATEGY -- Brian Eno
5. MARJORY RAZORBLADE -- Kevin Coyne
6. FINE OLD TOM -- Tom Newman
7. EGE BAMYASI -- Can
8. PARIS 1919 -- John Cale
9. BOULDERS -- Roy Wood
10. LARKS TONGUES IN ASPIC -- King Crimson
11. SELLING ENGLAND BY THE POUND -- Genesis
12. THE DARK SIDE OF THE MOON -- Pink Floyd (I know I should pick one of
their "cooler" albums, but let's face it: it outsold everything else they
ever did because it was their best album by leagues)
13. LEGEND -- Henry Cow
14. TUBULAR BELLS -- Mike Oldfield

And any of these could be #15:
MASS-MEDIA STARS -- Acqua Fragile
PARADIESWARTS DUUL -- Amon Duul I
WHATEVERSHEBRINGSWESING -- Kevin Ayers
ELECTRIC LIGHT ORCHESTRA -- Electric Light Orchestra
ANGELS EGG -- Gong

Clearly, I'm more of a Canterbury/Virgin/Krautrock fan than a Tull/ELP/Yes
fan.

S