Saber reading Shinji the riot act in chapter 9. And incidentally keeping Sakura from killing him.
Cut to next scene, and he's stumbling away with a bloody nose and broken ribs.
In Chapter 4, Shirou gives Shinji a scathing lecture, and threatens to beat him unconscious if he doesn't shut up. When the idiot tries to talk back, Shirou calmly asserts that he was serious. Shinjishuts right up.
Even better is that Shirou doesn't know what to do with Shinji (due to their history), but there's no way he's letting him off scot-free for his crimes. If there's anything in this story that makes pre-Archer Shirou a budding Badass and "Hero of Justice", this speech is it.
Chapter 14: EXCALIBUR. That is all.
From Chapter 9-11: the Enemy Mine between Archer, Lancer and True Assassin against Caster Alter and the fight that follows.
Most particularly, Lancer manages to unleash a successful Gae Bolg towards the end of the conflict. Sadly, it fails to kill her, and he is subsequently consumed by the Grail.
Say what you will about True Assassin, but he definitely had his moment in that fight.
Assassin: "You Missed."
Chapter 14: Despite believing that he might be killed in the process, Archer manages to blindside Caster Alter with Gram (the sword of Sigurd), leaving her to flee licking her wounds afterwards and preventing her from corrupting him with the Shadow.
More than that though, the Shadow actually DID try to corrupt him, as a glob of it and Caster Alter did a sneak attack on him, but Archer simply pulled a holy sword and slash it off. Something that manage to corrupt Cu Cuchulain and even Beserker failed to corrupt him.
Chapter 16: Saber and Berserker (and later, Archer) versus Gilgamesh. It is utterly glorious.
Especially when Archer manage to deflect frickin' Ea with Rho Aias, granted it pierce through like it was tissue paper, but it was strong enough to reduce Ea's blast(which is more powerful than Excalibur) to relatively harmless wind gust!
Before that, the same chapter depicts Ilya's Shut Up, Hannibal! to Gilgamesh. She's really come a long way since the story's start, hasn't she?
Shirou going after Caster like something possessed in response to her hurting Ilya, its awesome enough to get Archers's approval
A partially corrupted Saber slaughtering Berserker Alter while No Selling everything Caster can throw at her and then finishing him off with an EXCALIBUR blast to the face