Favorites:
(1) Emerald Graves. Most beautiful area, with a really nice mix of things, both in story and in gameplay.
(2) Storm Coast. The almost perfect sea atmosphere captures me every time I return.
(3) Crestwood. I love the landscape, and the way it changes after you close the rift in the lake.
So-so:
(1) Western Approach. Really good mood, good-looking fortress and some beautiful locations, but things get tedious after a while.
(2) Fallow Mire. Good mood again, and some interesting exploration rewards for a lore fanatic, but combat is annoying. Also: undead.
(3) Hissing Wastes. A really well-designed location with too little to do for its size. Quests there are not so well developed.
(4) Emprise du Lion. A very beautiful location, but what I do there fails to appeal. I'm not sure why, but I'm always glad when it's over.
Disliked:
(1) Exalted Plains. A PITA to get around, collection quests without markers, too much fighting, and undead.
(2) Forbidden Oasis. A PITA to get around.