I voted for a TSR item... T1-4 The Temple of Elemental Evil.    We had such a great time playing that one.

Another fun one for our group was S4 The Lost Caverns of Tsojcanth.    I think that module killed more characters than any other I can think of.  lol  Was still great fun.

Hmm... I never played the R modules, but I may have to read through R3 and R4 to check them out, based on Frank's comments.    I was gonna get to them anyway, but now maybe they will move to the top of the stack.  

~Kat  ^_^

P.S.  I should mention that one of the most fun times I ever had running a game was actually running a homemade adventure.  Actually, it was a one-on-one game and I totally winged it.  lol  The player begged me to run a game and I didn't have anything prepared.  I ended up sitting down with him and we played for hours... until the sun came up, actually.  lol  Somehow things just all worked perfectly and an idea popped into my head for a plot in a town adventure, as we played... I remember impressing myself at the time.  lol  Anyway, even though I don't remember details about that game, we had great fun.  In fact, my friend gave me a great compliment by saying it was the best game he ever played and thanked me endlessly.    That was a fun all-nighter... and one of the only times I played a one-on-one game.

My best adventure, that I have run, is a tie between "Tallows Deep" and "Vesicant" both from Dungeon Magazine.  Tallows Deep was my first tutorial in making really vicious but not instantly deadly traps; as well as a good primer for playing lesser humanoid monsters intelligently (the final battle with the goblin leader comes to mind).  

Vesicant taught me that sticking to the Monster Manual entry for terrain does not necessarily mean that you have to encounter said critters in that particular terrain (forests that house Green Dragons can be near enough to the coast to allow said dragon to be encountered in open water).  I addition it was a great example of how to run a dragon encounter intelligently (nearly as good as Into the Fire also from Dungeon Magazine fame).

~jeff

My best adventure(s) have always been the ones culled from whatever I had - rarely have I ran a module, itself (in fact, I have used only three as-is) and so, I treat them as more of "supplements" than adventures. I do have some I tnd to use more often, mostly for maps or encounters, or magic items, or NPCs, or whatever... but I just find it hard to shoehorn a module into my game, because my game is not typical.