Emancipation (A handful of it is really good, some fillerish, some outright bad. Didn't need to be a triple album)
Those Smashing Pumpkins reissues are REALLY long, makes Mellon Collie way longer than it already is. So I guess I'd say Mellon Collie and its reissue with tons of bonus tracks too.
drukqs by Aphex Twin too:
American Hunger (2006)
Damn, never heard this one but this is long as hell