The scene where Yuna, after a lifetime of preparation for becoming a summoner and defeating Sin, even being willing to die in order to give the people of Spira a temporary relief from sorrow, find out the truth about The Final Summoning used to defeat Sin in the past and promptly say "Screw Destiny, we're going to end the Vicious Cycle permanently, not just start it over" was her Crowning Moment Of Awesome. The rest of the party quickly follow suit, but it was her moment.
Yuna: No one. I would have gladly died. I live for the people of Spira, and would have gladly died for them. But no more! The Final Summoning...is a false tradition that should be thrown away.
Yunalesca: No. It is our only hope. Your father sacrificed himself to give that hope to the people. So they would forget sorrow.
Yuna: Wrong. My father... My father wanted...to make Spira's sorrow go away. Not just cover it up with lies!
Yunalesca: Sorrow cannot be abolished. It is meaningless to try.
Yuna: My father...I loved him. So I...I will live with my sorrow, I will live my own life! I will defeat sorrow, in his place. I will stand my ground and be strong. I don't know when it'll be but someday, I will conquer it. And I will do it without...false hope.
- And there's Auron's lines, of course.
Auron: "This is it! Now is the time to choose! Die and be free of pain! Or live and fight your sorrow! Now is the time to shape your stories! Your fate is in your hands!"