"Pirates II: Stagnetti's Revenge"
seems to be the porn equivalent of Citizen Kane.
(
Flapjack I spay a little mare for you, Thu 9 Jul 2009, 22:22,
archived)
You could argue Caligula was more expensive
but that was not just an out and out porn film
(
magnum, Thu 9 Jul 2009, 22:27,
archived)