Mon Calamari.
Zett Jukaska or whatever the last name.
Falcon's Cameo.
Clonetroopers (they are just awesome in the movie)
Scout Commandos (i loved those Scout troopers in ROTJ and it was great that Lucas give us these similar guys)
Opera scene.
Hooded Vader or Darkside Anakin.
Hologram of Sidious.
Only 6 mins of Dooku. (that gives me a funny feeling de ja fu, when the main character of a film series is killed off at the very start and has a minor role, did anyone else get that feeling too?
General Grievous.
Yoda vs the Emperor. (ultimatley exciting)