I've run most of my games in that world. I still have, and use, the first boxed set. I also have most of the From the Ashes books and use those. And I have the Gazetteer that came out with 3E and use that as well. I like it because it's the world that to me is the standard for D&D. While I like some things about Forgotten Realms, it's a little too much for my tastes. I like the backdrop of the Suloise/Backlunish ancient wars, the corrupt Great Kingdom, the rise of the dreaded Empire of Iuz, the Wolf Nomads, the Ice Barbarians, the Scarlet Brotherhood, Vecna and his Spider Throne, etc. In short, it has just the right mix of cultures and fantasy concepts for my taste of fantasy gaming. It also has enough information through the published material and fan websites that I can have plenty of detailed information when I want it, yet there is still plenty left undefined for me to fill in as DM. Many of my favorite classic adventures are set there, such as Against the Giants, the Temple of Elemental Evil, etc. which I've DMed for players in the past. I'm running a game there now, currently through my slightly tweaked version of the Return to the Temple of Elemental Evil. I'm running another game through the Dungeon Adventure Path in another part of the continent.