I like Pathfinder Chronicles: Gazetteer. Golarion is a world on the brink of disaster, with every nation looking for trouble with its neighbors, is in trouble, or both. And unlike fantasy worlds like Greyhawk or Forgotten Realms, major forces of good are few and far between. I like the sense of horror pervading throughout the area, with the Eye of Abendego -- a massive, supernatural storm -- off the coast; Asmodeus as a major deity of the Chelexians and a threat to everyone else; to such nations as Galt ("Eternal Revolution") whose populace beheads its leadership every few years.
Full review
Full review