Will shutting Reese down when he takes a shot at Mackenzie.
Will: Her name is Mackenzie, or Ms. McHale, and she's reported more news in one day than I have in my career.
Will telling Mackenzie "I'm in" at the end of episode 2.
Jim talking Maggie down from her panic attack in episode 3.
After Don, whom the rest of the staff have not been getting on with, stands up to Reese in episode 4, Will calls out across the room:
Will: "You're a fucking newsman! Don, I ever tell you otherwise, you punch me in the face!"
There's a small moment in the control room, where Joey the graphics producer has a Heroic BSOD, and Jake the technical producer turns to him and tells him to 'breathe regularly' when they don't have to put up the graphics announcing that Gabby Giffords is dead.
Will's reaction to it looking like Mac was using him to help her boyfriend's campaign for Congress. He is incredibly calm and kind, assuring her that he knows she didn't know that her boyfriend was using it for notoriety and that she is "annoyingly ethical".
Elliot got the crap kicked out of him chasing a story in Egypt: a couple of busted ribs, a broken arm, a lot of bruises. When he gets home, everyone cheers (and sends him a couple of strippers). When he walks into Charlie's office, Charlie immediately asks if he can hug him. No, because of the ribs. So Charlie gives him a kiss on the cheek.
Then Don wants Elliot to go on the air to show that foreign journalists are being attacked in Syria. It's not because Don wants to make Elliot into a news item, but it's because he feels guilty that Elliot was hurt trying to report the news (because of him) and no one will know about it. The smile on Charlie's face when he hears Don scramble to explain himself says it all.
The Rudy references, especially the one at the end with the entire news team filing in to Will's office to give him checks to help pay for Khaled's release. And the hug Will and Mac share.
The look on Will's face when Mac says "Happy Valentine's Day". Just... the look on his face. Damn. Damn it, Jeff Daniels.
Before this, the way the entire team, including Elliot who had just returned after being attacked, is out trying to get Khaled released.
Will: And if there's any fallout, I'll be standing right next to you and in front. I'll always be standing right next to you and in front.
Don telling two airline pilots that the United States killed Osama bin Laden. Although we don't get to see their reactions, Lonny (who was an MP in the US Army) gets to tell two New York City police officers. If there were any groups of people most affected by the news, it'll be them.
An additional touching detail to this scene: Don stops his tirade as soon as he notices the insignia on the pilot's name tag. Though it's never revealed within the show, the insignia actually belongs to United Airlines. Two of the four planes hijacked on 9/11 - including the plane that went down in Pennsylvannia thanks to the heroic resistance of the passengers - were from United.
"The Greater Fool".
Jennifer: I know what a greater fool is. And I want to be one.
Will: [to Mac] Camelot. She's the kid at the end of Camelot. [to Jennifer] Ask me again.
Jennifer: I'm sorry...?
Will: Ask me your idiot question again.
Jennifer: What makes America the greatest country in the world?
Will: You do. Hire her.
In Season 2 we find that Will's first day at the anchor desk was on September 11, 2001. With all the other anchors grounded at airports or otherwise immobilized by the national emergency, it fell to Will, who was only the legal correspondent at the time, to anchor the worst possible tragedy imaginable. By midnight, he had been on air for almost 16 hours, and he gave this speech.
Will: I have been searching for a, uh, biblical quotes. None of them... We don't know many are dead. It's going to be a lot. It's going to be thousands. We don't know who attacked us, we don't know what's coming tomorrow, and I don't know what I'm doing. But I'll make you this promise... I'm going to be with you all night. I'm not going anywhere. I'll be right here.
Before that, Charlie, who had likely never spoken to Will before, personally brings him some coffee, and words of encouragement.
Charlie: I've been learning about you... You're the oldest of five?
Charlie: Had to protect your mother and siblings from a pretty mean, drunk, bully of a father, sounds like.
The Reveal of Will's message to MacKenzie on the night Osama was killed.
Will: Hey Mac, it's me. Look, I'm not just saying this because I'm high. I've never stopped loving you. You were spectacular tonight. (Beat) Can you believe we got Obama?
Even though they got kicked off the bus, it was nice to see Hallie and Stillman standing up for Jim's call for better reporting on the Romney campaign.
Also Jim and Hallie kissing
Don keeping Sloan company after nude photos of her are leaked online throughout the night, even though he's supposed to be at a rundown somewhere, is really, really sweet.
Played for Dramatic Irony in Red Team III; when the crew is debating about whether to green-light the Operation Genoa report. When everyone turns to Will, he gives his opinion: that he implicitly trusts Mac and Charlie, who believe their sources are solid. This is the first time he's openly stated as such in front of the crew. Sadly, thanks to the Framing Device, the audience already knows this is set up to backfire.
When confronting Will about his confidential source for Genoa, Will says that he would only reveal it if Mac was being tortured. She acknowledges this as a CMOH in universe.
She also calls ACN 'My house', and that she loves it very much.
The season 2 finale is chock full of these, starting with:
Don's immediate reaction to run the Petraeus affair story is not for sensationalism, but so News Night can gain back some cover for the Genoa debacle. He quickly changes position when reminded of his journalistic integrity.
The entire senior staff unanimously agreeing to resign if Will, Mac and Charlie resign.
Don: We gave you a bad story. It's our responsibility. There are principles of... principle here on character and responsibility.
Will: Who put all this in your head?
Don: (without missing a beat) You did. Now can we go back to work?
Will: (long pause) You expect me to get all choked up?
Sloan telling Will that he insulted everyone a little by not assuming the staff would stand behind him, Charlie and Mac, and that she's a little insulted too.
Will abandoning his chair and forcing Elliot to take his seat so that the viewers can get used to Elliot before Will has to resign.
Will sincerely apologizing to Mac for the ring prank.
Don almost in tears when he confesses what he really wants.
The entire control room silently but visibly outraged by Jane, the DC bureau's anchor's offhanded remark to 'not drop sarin gas', Mac's defense of her crew, and Charlie shutting Jane up with a direct order.
Neal's persistence in changing Mac's Wikipedia details as a final gift for her.
Sloan discovering who bought her big boring book that she didn't autograph (spoilers: it was Don) and FINALLY giving him a passionate kiss.
Don: What I have can't be taught...
Jim telling Maggie that what happened in Uganda and Daniel was not her fault, that she is a tough and brave person, and convincing her to tell Lisa and patch things up.
Charlie deciding he and Will are not going to quit
Will FINALLY realizing he's in love with Mac and FINALLY telling her he loves her, and asking her to marry him. The fact that he's a babbling mess is just that much more adorable.
Will: Except for what she did wrong, she did everything right...
Reese, being given the power to decide whether to fire Charlie, Will and Mac over Genoa, and deciding no, he's not accepting their resignation, he's not making his decisions based on a petition, he's going to give Dantana money when the federal court tells him to, and that the team handled the story as best they could.
Will announcing to the entire crew that the only reason no one is resigning is because he says so, and then he introduces the future Mrs. MacKenzie Morgan MacHale MacAvoy.
As the entire crew is celebrating a night's hard work covering the elections, Reese, Rebecca, Charlie and Leona are rounding up whatever friends ACN have left and preparing for the fight ahead.