1) Empire Strikes Back - Because Luke has become a better warrior, and because of the drama and intensity in the Luke/Vader dual at the end.
2) Return of the Jedi - Because Luke finally becomes a Jedi, proves himself, and helps his father beat the emperor, great ending.
3) A New Hope - Because of the good chemistry between the actors that lasts the trilogy, and the rescue of Princess Leah/Escape from Death Star
4) Attack of the Clones - because Ben really kicks a lot of butt in this one, and we see he has grown more since the last movie.
5) The Phantom Menace - Favorite themes of this one are how it follows Qui-Gon and his apprentice Obi-Wan, seeing them in action together.
Looking forward to Episode III 😄