STAR WARS - The new Falcon liftoff from Mos Eisley. I hate seeing three consecutive shots of a ship flying/landing/whatever in one direction, but they didn't chop up the scene to fit the new shot in, so it worked.

EMPIRE - The original score got cut up and butchered - every shot of the Empire's fleet used the same audio clip and the scene where Leia and Lando chased down Boba Fett cut out in the middle of the climax. The Special Editions edited those scenes to use the music John Williams wrote.

JEDI - I thought the new clips in the end were fun. Minus the gungans. Naboo got its finale in Sith. Also didnt mind the new shots of Boba Fett.