There were 185 adventures made by TSR or WotC for 2e. The reason that you will get very little consensus as to which were the best is because the vast, vast majority of them were made for a specific setting or sub-setting. Rather than making generic modules that everyone could use, TSR was making very specialized adventures for very specific target groups. Thus, not as many people played each one.
The Aceaum has an article on the print run of TSR adventures. In the 80's modules were usually printed in the hundreds of thousands. In the cases of some, B2 and S1 specifically, over a million were printed. Think about that. If every one of those were played just once by a party of 4, that's an awful lot of people with a shared experience going through those dungeons. Adventures in the 90's were generally published in print runs of about 10,000, sometimes less, rarely more. Which means that plain and simple fewer people were playing those adventures.
Thus, in the case of 1e and B/X D&D, you're going to get a relatively narrow consensus on the top 10 or so adventures made. With 2e, you might get every single poster giving you a different favorite.
My prediction is that the more universally applicable adventures made in the later 2e period will end up being the most popular in this thread. We've already seen Rod of 7 Parts and Return to the Temple of EE get multiple nominations.
R.A.