From Morrowind, the Hungers... just scrawny, long-limbed nightmares. Creepy things.

http://www.rpgamer.com/games/other/pc/elder3/themes/mw_hunger800.jpg
On Oblivion, I always loved and loathed coming across daedroth. They're big, mean and surprisngly fast. Felling one felt like an acomplishment.
http://www.giantbomb.com/daedroth/51-966035/
Hoping to see both rendered in Skyrim with that shiny new engine...
( Were I to ignore the rules set forth in the op, I'd say Khajiit. What can I say... I liek kittehs. :3c )