I've been running a Mystara campaign since 2012, with just over a year's worth of breaks for other games interspersed. The PCs are 20th level and getting on their way to Immortality, using adapted Immortal rules from Wrath of the Immortals. This of course means the campaign won't be done for another few years while they (hopefully) achieve this, since this requires a bunch of impressive feats on the part of the individual characters, any single of which would be the finale of most any other campaign. Then they will play in a campaign where they play their first worshippers.
I grew up playing classic D&D modules that became rites of passage for groups. It was fun comparing stories on how each group made it through the Temple of Elemental Evil or died horribly in the Tomb of Horrors.
There are several Paizo adventures and modules that I think are worthy of classic status such as the Crypt of the Everflame and its sequels. For adventure paths, I'd put the three Runelords paths up there along with Iron Gods, Wrath of the Righteous, Kingmaker and Ironfang Invasion.
Of course, I haven't played or run everything yet, so there are plenty more I'll most likely want to add before it is all said and done and long before I move on to Second Edition.
AP: Strange Aeons, given a creative group and a lot of work filling in the gaps, is an absolute delight.
AP runner-up: Rise of the Runelords is more "classic" D&D than most D&D games I've played.)
Module: The Moonscar. Succubi on the freaking moon? Where do I sign up?
Module runner-up: Feast of Ravenmoor. A solid low-level adventure that hammers home several core mechanics that may not have been heavily exercised yet and has plenty of potential for kicking off later plot hooks.
Homebrew: Jacob's Tower by Zenith Games. I liked it so much I worked it into the fabric of my own campaign setting.
Homebrew runner-up: The ever-evolving list of house rules, custom magic items, artifacts, and out-of-context player quotes my players and I have built up over the years.
blahpers, can you elaborate on some of that "work filling in the gaps" for Strange Aeons?
I was looking forward to that one, but the later books in particular were a real disappointment. What sort of work did you and your group do to overcome that?
Full disclosure: I haven't run this yet, though I've planned through the first three books and have read the rest in preparation.
The first three books can basically be run without any changes. That doesn't mean they wouldn't benefit from some. For example, I'm swapping out the cannibals in Book II because (1) I find them problematic and (2) since there isn't much of a way for the PCs to learn why they were there, they seem gratuitous. But for the most part they're enjoyable as is. I particularly enjoy Book I's unusual conditions for an AP start and the way Book III ties up the reason for those conditions.
Books IV and V are a bit rougher. I expect that I'll have to rewrite a major chunk of the plot in Book IV+, including the narmy mind messages from Grandma Yith, to better fit the mood of the game. But I'm used to that sort of thing. The whole PC immunity to X-D thing is odd, though, like it wasn't really thought through. I'm still figuring out how to revise it to make sense--or to *not* make sense in a way that feels thematic.
Book VI will be the toughest for me. It's not because the material is bad but because it's basically unfinished. The writers had to cover a lot of area in that book, and it shows--when it comes to NPCs, the text basically just dumps a couple of sentences of motivation and leaves everything else for the GM to figure out. That was pretty disappointing, but I can afford to put the work in over the months it'll take to get that far (assuming they do make it that far).
Some of the ambiguity of the later books is to be expected. The first three books leave quite a bit to the specifics of the PCs' prior relationship to Lowls, so one might expect that after they recover their memories there'd be enough variation in players' reactions to warrant leaving some gaps to fill. But until I get there I'm not sure I can really judge it.
Since turnabout's fair play, what was disappointing to you about the later books? Is there something you might have done differently in retrospect?