I'd like to see a rematch of one of my favorite fights of all time, Royce Gracie vs. Kimo. The heart that Kimo displayed throughout that fight was amazing and the grappling was very good. If we were under modern rules that would now prevent Gracie from grabbing Kimo's hair, headbutting and smothering him, the fight would only get better. I would also like to see Andrei Arlovski fight Ken Shamrock. Ken's getting older, but age is less relevant when you carry the ability to submit the opponent in the blink of an eye.
Armbar, Heel Hook, Kneebar, whatever. Give me a joint and some leverage, it's over.