Obi-Wan Kenobi: [Screaming in anguish at Anakin.] You were the chosen one! It was said that you'd destroy the Sith - not join them!
On Utapau, when Obi-Wan faces off with Grievous, Grievous sends 4 magna guards at Obi-Wan. Obi-Wan force-pulls something from the ceiling to crush the droids. But in the ensuing fight between Obi-Wan and Grievous afterward, the ceiling thing and crushed droids are gone.
In the scene where Darth Vader and the Emperor are looking out onto the unfinished first Death Star, keep an eye out for a young Grand Moff Tarkin (played by Peter Cushing in "Star Wars").