WayneLigon said:
[...]I saw no need to make Ravenloft into it's own setting; that was just chasing after the Vampire crowd who probably were not going to play D&D anyway.[...]
Just a note: Ravenloft's first incarnation as a full-fledged campaign setting (the "Black Box") was released
before Vampire: The Masquerade (1990 vs. 1991), so it isn't accurate to say that Ravenloft as a setting was developed trying to appeal to Vampire players.
As for my personal favorite, even though I loved the Black Box, with its unique approach to villains, I think that the Domains of Dread era was when the setting matured into a cohesive campaign world, without the need to always drag characters from other settings for a "weekend in hell" whose only purpose was to escape from the dread realms.
After saying that, though, I feel that the highest potential for the setting was achieved with the 3e supplements, when the setting was put in the hands of capable long time fans who continued the work that Steve Miller and William W. Connors started in DoD, developing the world as a viable native world for the PCs, and producing much needed information, like the gazetteers that, as was stated before, detailed the Core in greater depth with political, economical and social relations among the domains, and not just a patchwork of differently themed lands.
And yes, the 3.5 hardcover was just an update to 3.5 rules, with the addition of a smattering of rules that were generally perceived as ill-conceived among the fans.
I don't own the
Expedition to... version of the adventure, but from what I've read I wasn't greatly impressed. It seems that it departed from the original adventure's gothic horror roots into a more dark fantasy theme (not to mention the illustration of the Dread Elf Vampire Strahd...

)