Well, my 3-year old seems to prefer the OT. He refers to all the Star Wars films as "Green Man" - I suppose it's because Yoda has made an impression on him. Given a choice as to whether he wants to watch "Green man with boy in" (Ep. I) or "Green man with Luke in" (Ep. IV) he will always choose IV.

He's also watched parts of my laserdiscs (Big Green Man) but I don't think he appreciates that it's dubbed in French. He does however understand that Daddy has made Big Green Man into a little DBD, and he's waiting for me to do the same with Ep. V.