Henry
Autoexreginated
My answer is partly influenced by nostalgia, and not by the flavor, but by who provides it:
I still have to go with Forgotten Realms.
Even beyond his and other authors' writings, to listen to Ed Greenwood tell Realms-Lore is like listening to a history professor talk lovingly about a subject he has taught his whole life, or like listening to a native scholar of the lands chatting jovially about past events as if current-day. Ed Greenwood breathes and sleeps Realms-Lore, and listening to him it shows through. As much as I like Eberron, give Keith about 10 more years and he'll sound professorial on the subject like Ed does, and look the part.
The Realms felt old the first time I read about them 20 years ago, and rather than feeling like stuff was "created" for it, it's as if reams of material are always coming to light. Part of this is my nostalgia, and the other part is the loving care that most of its authors have lavished on it as well over the years.
My second-runner up is still Dragonlance, but mainly because people have created poems, songs, recipes, maps, and cultures for this setting. It breathes with life outside of combat and adventuring that many other settings do not.
And in truth, the winner probably SHOULD be Tolkien's Middle-Earth. So many more people have created for that world than any RPG, and the loving-care by 3 generations of fans would make any other setting pale in comparison.
I still have to go with Forgotten Realms.
Even beyond his and other authors' writings, to listen to Ed Greenwood tell Realms-Lore is like listening to a history professor talk lovingly about a subject he has taught his whole life, or like listening to a native scholar of the lands chatting jovially about past events as if current-day. Ed Greenwood breathes and sleeps Realms-Lore, and listening to him it shows through. As much as I like Eberron, give Keith about 10 more years and he'll sound professorial on the subject like Ed does, and look the part.

The Realms felt old the first time I read about them 20 years ago, and rather than feeling like stuff was "created" for it, it's as if reams of material are always coming to light. Part of this is my nostalgia, and the other part is the loving care that most of its authors have lavished on it as well over the years.
My second-runner up is still Dragonlance, but mainly because people have created poems, songs, recipes, maps, and cultures for this setting. It breathes with life outside of combat and adventuring that many other settings do not.
And in truth, the winner probably SHOULD be Tolkien's Middle-Earth. So many more people have created for that world than any RPG, and the loving-care by 3 generations of fans would make any other setting pale in comparison.