I’d have to admit to being biased (I was a significant participant) but I’d argue that the “Contact with the Great Beyond–Psychics like Praagh” takes this title. It was a furious knock em down drag em out debate right to the very end.
The others are games, chit chat, or all purpose repositories of different conversations about one subject (such as the Diablo2 thing) rather than a single continued conversation.
Although I don’t think it was the longest, the one that started on 9/11 was shut down after 400 posts. I think that thread was the quickest to grow, correct?
I remember a couple being shut down at about 10 pages. Apparently there was a performance issue at that length in the older version of VB. It’s like all-time and modern-era records in baseball.