On a related note, I showed my girlfriend the OT about two months ago. She had never seen it, but knew all the cultural memes. She grew up in an all-girl house and was just never exposed to them, although she had seen parts of them on TV while at friends/families places. She likes Harry Potter, LOTR, Spiderman, anime, stuff like that, so I figured she might enjoy them, although she doesn't know older movies and I knew she wouldn't treat them as though they were on equal ground to newer fantasy classics like some of the above.
-ANH: We watched the 1977 GOUT version. Overall, she liked it, found the characters amusing. She thought R2D2 was cute, predicted that Han Solo is "a jerk but then you find out at the end that he is a nice guy after all," and found it an entertaining and funny film, although I doubt she would want to watch it again on her own willpower.
-ESB: I'm not sure if she liked this better or not, but she appreciated the better production values, and the more adult nature. We watched the 2004 edition, because the changes weren't so intrusive. She didn't have much to say about this one, other than finally knowing the full context of a lot of famous quotes.
-ROTJ: Watched the SE because I never owned the GOUT. Most of her comments were made in relation to this film, mainly because of its flaws. Of course she thought the Ewoks were cute, but she noticed that the acting and dialogue was bad, especially Han Solo. A lot of other things, like Leia being Luke's sister and the whole romance triangle, made her laugh, and all the puppets and kid stuff. In general she said at the end that "it's like they didn't take it seriously anymore", that the makers sort of threw this out there. When Hayden came on at the end she did a double take and said why there was a guy "giving the creepy uncle stare." (I later explained and showed her the original, which she said made more sense) When the final scene of Ewoks dancing came on (this was the more sombre SE version, remember) she said that there had to be one more serious closing scene to tie all the story up in a mature way and was shocked when the iris went to the credits.
I haven't shown her the prequels. Maybe one day. Given her misgiving about ROTJ I am sure she would find them hard to stomach in places, but I am also sure she would appreciate the more snazzy visuals as well. I wanted her to be able to enjoy the OT, which is why I showed her this first. I can imagine her, like most people--and probably myself, were I in that situation--would find the sylistic incongruity and story/character re-focus that comes between ROTS and ANH to offputting and confusing. It's better to let people appreciate vintage films in the context in which they were meant to be seen (some SE misgivings aside).