This troper finds it disappointing that nobody else has mentioned the fight between Exia and the GN Flag. It may be short, but it is still a worthy CMOA.
Setsuna: "There's another one? It's a Flag... With a Pseudo Solar Reactor."
Graham: "I've so wanted to meet you. I've wanted to meet you so much, Gundam!"
Setsuna: "That's a Beam Saber."
Graham: "I will avenge Howard and Daryl with this GN Flag!"
Setsuna: "He's hailing me... So it's you."
Graham: "What's this? You're that boy. It seems that our destinies have been connected all along. Indeed! WE WERE DESTINED TO FIGHT EACH OTHER! I FINALLY UNDERSTAND! IT WAS YOUR DISPLAY OF OVERWHELMING POWER THAT STOLE MY HEART. That feeling I had, could only be called 'LOVE'!"
Graham: "But if you go beyond love, it becomes hatred, just as people turn on each other when they take religious faith too far!"
Setsuna: "If you know so much about it, then why do you still fight?"
Graham: "You're asking a soldier why he fights? Don't be ridiculous!"
Setsuna: "YOU'VE BECOME TWISTED!"
Graham: "YOU MADE ME THIS WAY! THIS IS BECAUSE THE GUNDAMS EXIST! That's the real reason I'm taking you out. I don't care about the rest of the world. THIS IS MY OWN WILL!"
Setsuna: "Don't kid yourself. YOU'RE A PART OF THIS WORLD AS WELL!"
Graham: "Then consider this the voice of the world!"
Setsuna: "YOU'RE NOT! YOU'RE JUST FORCING YOUR OWN DISTORTED EGO ON OTHERS! And now I'm coming for you... TO CUT THAT TWISTED PART OUT OF YOU!"
Graham: "Well said, Gundam!" GN Flag and Exia impale each other. "You see Howard, Daryl... I've avenged you."
- It's not just that battle that was awesome. It's the very existence of the GN Flag. Graham, lunatic that he is, rammed a Gundam engine into a Mook suit! The idea alone is pure awesome. And then he goes and kicks Setsuna's ass with it, just as the poor kids was celebrating defeating Alejandro Corner. We salute you Mr. Aker.