Superape may be my favourite reggae album, but it's not striclty a dub album...
Still, I don't know, since there are so many options - so let's try a top 5:
Creation Rebel - Starship Africa
Black Uhuru - The dub factor
Yabby You - Beware dub
Scientist - Heavyweight dub champion
Burning Spear - Living dub vol. 1
Augustus Pablo - King Tubby meets Rockers uptown
(o.k., I admit, it's a top 6 - so I really have to stop here...)