Let's Talk Modules
I am not big on going through modules or on running most modules, they have to be really cool in order to run them. I cannot improvise as much with a module and as a creative person, I always thinking that some portions are added simply as filler because the author did not know what to write or needed more pages.
My Favorite Modules
Ravenloft - I6
Of course, I loved this, everyone loved that the vampire had so many things going on and the course of the module was determined at the beginning with a few random variables... One of the only modules that was never the same when it was run.
The Vampire was intelligent and required you to play him as such... It set the tone for playing for many people. He had different motives based on the random factors determined at the beginning of the game.
The Isle of Dread - X1
You could drop this on any campaign world and run it... it was always fresh.
Dragon Lance - DL1 / DL2 / DL3
The first 3 are the top ones in this series, never cared to play beyond that simply because it really was made for running with the pregen characters and never felt right if they were not used. Of course my players and I wanted our own characters so this got boring after the third one.
Sabre River CM3
This is a module that takes a clever and smart DM to manage, it works on several layers and the monsters are tough as nails.
The Isle of Dread and Tomb of Horrors are 2 modules that everyone needs to go through. I did not the TPK* aspect of Tomb Of Horrors
TPK - Total Party Killer