Uhura (smugly): Hello, boys! I've always wanted to play to a captive audience.
Only Kirk could have the balls to challenge what is supposed to be the Almighty.
Kirk: What does God need with a starship?
McCoy: Jim, what are you doing?
Kirk: I'm asking a question.
"God": Who is this creature?
Kirk: Who am I? Don't you know? Aren't you God?
Sybok: He... has his doubts.
"God": You doubt me?
Kirk: I seek proof.
McCoy: Jim! You don't ask the Almighty for his ID!
"God": Then here is the proof you seek. *zaps Kirk with lightning, knocking him backwards*
Kirk: Why is God angry?
Sybok: Why? Why have you done this to my friend?
"God": He doubts me.
Spock: You have not answered his question. What does God need with a starship?
Don't knock McCoy's reaction to 'God's' lashing out at Kirk.
"God": Do you doubt me?
McCoy: I doubt any god who inflicts pain for his own pleasure!
Spock's pain was slightly Narmish, but after McCoy's genuinely affecting experience of his father's death ("Release me..."), Kirk's refusal to share his pain is also affecting.
Kirk: I don't WANT my pain taken away, I NEED my pain!
Scotty is all kinds of awesome in this movie, first he avoids Sybok's Mind Control (unlike everyone else on the crew), then he breaks Kirk and the gang out of jail, and then he manages to (partially) fix the transporter! To quote Kirk, "Mr. Scott, you're amazing!"
The climax of the film. Kirk is running from the fake God alien, only to have a Klingon warship appear in front of him and blast "God." Kirk expects the Klingons are about to kill him, only to be beamed on board to see that the gunner is... Spock. Spock justshot a Sufficiently Advanced Alien pretending to be God.
General Korrd. Spock, too, telling him to stop pitying himself and do it. (Guess he got the hang of those "colorful metaphors" after all!)