You know the Jedi battle at the end of Clones? Was it just me or did it seem really... flat? All the necessary ingredients were there, but it just didn't grab me.
Well, my favourite is Ep 4, because it always takes me back to being an 8 year old kid staring open mouted at the screen.
In the context of the original question, I'd probably go for Revenge of the Sith.