Probably "Lather" which is also one of my favorites
Since I'm not aware of a quadruple album (though I'm sure thy exist) the answer would be any triple albums I've heard (though some double albums might be longer- who has time to check lengths- that's what she said), so "All Things Must Pass", "Sandinista", "Thing-Fish" (jesus forgot it was that long- that's what she said) Tom Waits' "Orphans" and "Will the Circle Be Unbroken" by The Nitty Gritty Dirt Band. And I guess "Metal Box" was released as a triple album even though it's only an hour long. That Rotten- what a prankster!
"Melon Collie" and "The Fragile"- we were *raised* on arrogantly epic depressfests BillyGoatGruff! How you likin the NIN so far? Feelin angsty yet?