@OP

Maybe you should specify whether you really mean whole "scenes", or sequences, judged by all their aspects (acting, feel, maybe even dramatic quality), or anyone here can just name some 2 second moments they find cool.

For instance, I like almost every introduction, montage and transition sequence in those movies - the opening scenes after the credits, the closing montage, the panorama shots shortly before the real scene begins, various arrival sequences like the invasion army's, Grievous', underwater city, Coruscant... the scene where Anakin looks for the assassin in the bar... in fact, whenever there are no people talking, the prequels are pretty cool!