I'm really hoping that Anakin becomes Vader and Palpatine announces that Vader will be his new apprentice. Dooku gets pissed at the betrayal and the two fight, with Vader crushing him like a bug.
Remember the battle between Dooku and Yoda? It seems to me that the reason Vader and Obi Wan dueled was for the same reason Yoda and Dooku resorted to lightsabers. Knowledge of the Force alone wouldn't decide the battle.Dooku would appear to have greater skill with a lightsaber AND a greater range of force-skills (Vader was never seen to use force-lightning, which appears to be an advanced skill).