I'm also a fan of The Grey Citadel which combines role-playing, investigation and high-stakes combat in one delicious module.
Hmm. I'm glad you mentioned that one. A while ago I was participating in another thread and that module came up with high regard. I told them thanks, and said I would buy it. However, being prompted by your comment I went to review my copy, as I don't recall
anything about it, and it turns out I really don't
have it. So immediately after writing this post I'm going to head out over the Internet to buy it somewhere, if it's still around. Thanks.
The Secret of Bone Hill - This module showed me early in my DMing career how to do a sandbox style game.
Yes, agreed. In fact, to answer the OP, here is my favorite "module" from way back: I used to run B4 The Lost City, and then with
heavy conversion I would place L1 The Secret of Bone Hill onto "The Island of Death" in B4's underground city. The two modules took a
huge amount of time to finish, even back then when my jr. high buddies would come over twice a week to play.
Man, that was so much fun. I can still remember the dark heavy wooden dining room table, with all my buddies positioned around it. Every now & then crazy Cyrus would join us for a game, bring weapons, and try to
act out the fights. Good times.
I also like the B4 module even now, because Zargon (the BBEG) was updated to 3.5 in the book Elder Evils.
Anyway, nowadays the modules that I've had the most fun with are the DCC module, The Cage of Delirium, and the Bleeding Edge module, Dirge of the Damned. For Cage of Delirium, I got a hard copy so that it came with the CD, and the group I'm playing with actually
likes hearing the creepy music as we go through the rooms. And for Dirge of the Damned, I just like that it's a bard-centric module that involves a play and a murder-mystery. I like these more "balanced" modules where the fighting is only part of a bigger game that includes skill checks, character interactions, sleuthing, etc. I also enjoyed the DCC compilation The Adventure Begins for something similar. I mean, all the modules in that compilation are hack & slash, but a few are really trappy and rogue-friendly. I had a great time with those mini-modules. I'm in favor of anything that mixes up the standard pattern, "I hit, is it dead yet?"
The only problem I have with Cage of Delirium is that the haunted mansion is
so big. I mean, I drew it onto a Chessex megamat (4 feet by 3 feet), but discovered that each floor is so huge that I need
two battle mats. The floorplan ends up requiring me to put two dining room tables together, just to display one level of the map. Since that isn't always feasible, I end up keeping each battlemat separate and we plop 'em down as the players explore. Kind of a pain, but I still love the module.