About ROTJ, I must say that it's got much more going for it than any of the prequels. Not only is it the climax, but it is masterfully directed by the late and great Richard Marquand (so sad he didn't get to keep on directing, he was quite talented). The atmosphere is steely and dark on the Empire's ships, and lush with green on Endor. The two styles get to clash wonderfully during the final battle, and this one definitely has the highest production values. Lucas got his hands on the script for this one, but aside from the Ewoks (who are tolerable in my opinion since they did almost kill the heroes and played drums with a stormtropper head...can't say that for the Gungans) Kasdan works his magic again especially in any scene with Luke or Vader.
The prequels have there merits, but they have yet to achieve any sense of timelessness like the OT. Nothing new or exciting is presented in them. Revenge of the Sith could surprise everyone, but let's use the confetti for New Years 2005 just in case.