I not so secretly enjoy Con Air. I bought POTC World's End because I read how good the picture quality was in 1 and 2. The only part in World's End that I think looks good is the good bye scene on the beach.
An interesting article to google is about The 5th Element. The first high def release was atrocious, the second much better. I can't remember if it was HD DVD or Blu Ray.
Close Encounters of the Third Kind also looked pretty darned good. The picture isn't smooth as glass but overall it looked great. The last time I watched it on DVD it looked awful.