Definitely eye. When you take one clean on the chin its more that you lose focus a bit and things get a little dizzying. But if you get punched in the eye, its all pain, your eye is full of very sensitive nerve endings.
There is however one pain that has surpassed all others I have ever felt. I've blown out my knee, I've broken bones, I've been kicked in the face, and none of that compares to a well timed spinning back kick to the liver.
Scott Smith, I know that feel.
Sig courtesy of that photo-matic magician limba
I went out the way that I fight. I went out on my shield. That’s it. Done. --Chuck Liddell
My goal is to end my opponent --Carlos Condit