I have always loved deserts in videogames, the setting, the music, the long stretches of sand and dunes with piramides glistening in the distance, and ancient crypts filled with the walking dead.

Age Of Conan had the best music and zones in that theme, ever.
Diablo 2, another great example.
EQ2 Desert of Flames, again, great music and gfx.

Jungles I dispise, thanks to Feerun in EQ2 or FF11.
Snow? Seen enough of it allready.
Asian chinese/japanese. Hmmm perhaps, they can make some very nice armor and weapons with that sort of theme.
Underground? Original.
alien? No thanks, the Burning crusade did that, and it just looks out of place now. Great sky gfx though.