Akrasia said:UK4 When A Star Falls. Best AD&D module of all time.
Wow, someone else who ran that! I had a lot of fun with that module, though unfortunately I wasn't able to finish it. I was worried, though, about the ending. It seemed like a TPK waiting to happen.
For my money, one of the best modules of all time is B7 Rahasia. The storyline with the trapped witches and the Rahib has tons of potential, and the witches make wonderful adversaries if they take an active role. I've DMed it three times, and each time was a blast.