-Dark Sun: Fantastic aesthetic, wonderfully different than the combined FR/DL wank of late era TSR. Too bad they had to push that metaplot. Perfect dungeoncrawl material for people sick of Ye Olde Classik Fantasye.
-Ravenloft: I like spooky shit. 3e iteration of the setting is the best one desu because it makes it function as a proper setting instead of a giant Haunted House Simulator, and guts the overt crossovers with the other D&D settings.
-Hyperborea: More Sword & Sorcery pastiche that you can shake an Atlantean Longsword at. Manages to feel both weird and grim but heroic and adventurous at the same time. The setting is PACKED with plot hooks and potential for exploration.
-Denethix: Thundarr the Barbarian meets WIZARDS meets every other post-post apoc science fantasy. Gonzo, in the best way possible; almost feels like a 2000 AD comic in RPG form.
-Hill Cantons: Unique without being overstated, Quirky without being too twee or ironic, Weird without being too edgy or unapproachable. Folkloric bent/acid fantasy bent instead of high fantasy means cool stuff like Moss Dwarfs and Slavic Bear Mercenaries mingling with weird Bowie-meets-Cronenberg extradimensional elves.