A: Any scene in the later ones with Hayden Christensen in them. LOL j/k
(well...maybe not TOTALLY kidding...

)
This is going to sound really weird but I'd have to say the very beginning of the original movie (which would now be Part IV) simply because it was new and exciting, and I saw it in the movies as a kid when it came out and we knew we were in for something amazing (back then the special effects were considered tripped-out-state-of-the-art).
Do you tend to be a very materialistic person?