In my humble opinion, Most fun to watch is definitely Rondo. Rondo has several different ways of putting a smile on your face. It can be a a ball fake, nice pass/alley, lay-up/dunk, a steal, a beast rebound against a big man... possibly all in one trip down the court.
The thing about B.Walker is the sport center factor. You just watch him waiting for some crazy highlight and the longer he's out there the more likely it is to happen.
What the two players have in common is boat loads of, that's right you guessed it, Potential.