Best Overall Concept - Dark Sun. I mean, c'mon. Imagine a world that was once lush with vegetation, but suffered a series of genocidal wars directed by a mad wizard (later overthrown and imprisoned by his own generals), which turned the planet into a barren, blasted desert. Now, resources such as water, wood, and metal (especially iron) are extremely rare, and the few centres of life and commerce on the planet are a series of city-states ruled by Sorcerer-Kings who wield godlike power. Life is often dangerous, brutish, and short and the only equalizer is the fact that everybody possesses psionic power to some degree. Plus, all the halflings are savage cannibals. How can you beat that?!
Best New Concept - Iron Kingdoms, because steam-punk + fantasy = Really Cool Campaign Setting.
Best Overall Setting - Homebrew, because you can tailor-make it to be whatever you want it to be. Personally, though, I prefer to run in FR (for that high-magic feel) or Scarred Lands (for a more gritty feel).
Worst Overall Setting - World of Synnibar.
Worst D&D Setting - Dragonlance. The events of the novels were so huge and world-shattering, it felt like the PC's just couldn't make any kind of difference. Alot of people accuse FR of the same thing, but Faerun is
Big , with plenty of places where your characters can shine. To me, Ansalon seemed very small so it was difficult to do anything without running into the shadows of the Heroes of the Lance. The fact that it had Kender, Gully Dwarves, and Tinker Gnomes was just adding insult to injury.
Of course, I'm anxious to see how the new d20 Dragonlance setting gets treated.