I showed both my children the Star Wars films at an appropriate age when they were growing up (it's a childhood rite of passage, after all). Obviously, I showed them in release order (and also made sure no one spoiled the Darth Vader twist). They were captivated by the original trilogy (and genuinely shocked by Vader's revelation), and didn't much care for the prequels. Later when the sequel trilogy was in cinemas, we went to see those which they liked to a point, but still prefer the original three.