Cam Clarke's performance as Kratos. Consensus seems to agree that he does better than the original voice actor.
Sheena gets several of these:
Right after Volt kills Corrine, who threw himself in front of her to protect her from a lightning blast, she proceeds to stand up and demand Volt to make a pact with her.
"For the sake of everyone who risked their lives to protect me... Volt! I DEMAND your power!"
The first time you have her summon a Spirit would also count.
Sheena gets another big one later when she fires the Mana cannon.
Arguably topped when she does her "impression" of it beneath the Tower of Salvation.
The first trip to the Tower of Salvation. It's simply unforgettable. Add in some Big Damn Heroes moments (from the party) and then the Renegades to an epic Boss Rush, with amazing Music. (Let's not forget, this is where the game shifts gears from otherwise generic JRPG to something much more epic.)
The way the party blackmail the Pope, with Raine both giving him the poison and then interrogating him before giving him the antidote, and Presea holding an axe to his face.
When Zelos shows up and reveals that he saved all of the seemingly doomed party members from their deathtraps and then proceeds to kick the crap out of Mithos with Lloyd and the rest of the party.
Or alternately, Zelos's final battle before his death where he gets those angel wings is absolutely awesome, even if he did lose.
Presea gets one when she frees Colette by destroying the force field around her.
Colette is actually much more of an Action Girl than people give her credit for, even if she's not on the same level as Sheena or Presea. Some of her highlights include:
Saving a woman from being executed by cutting the noose with her chakram.
Throwing her chakram at Kvar when the party first meets him, stunning him enough so that the party can proceed.
Fighting back when Pronyma tries to take her away. Especially since this is the moment she returns from her soulless state and then smacks the Desian away before destroying the trap the rest of the party had been caught in.
The majority of the fight scenes in the OVA's are done really well.
When Iselia is being attacked, Dirk joins Lloyd and Genis, and can be seen bashing up Desians with a Big Friggin' Hammer
When Sheena attacks the company in an Absurdly Spacious Sewer, she opens up the battle by jumping at Lloyd's face, and slapping a card on his chest. The physical force of her strike sends Lloyd flying, and then the card explodes.
Then, Kratos retaliates against Sheena. Diving at her, he jabs her in the stomach with the hilt of his sword, and then turns around and roundhouse kicks her in the stomach. Sheena does a couple ninja-flips backward, and then attempts to cast something (WHAT she was trying to cast is a mystery, at this point in the story). Kratos doesn't wait for her to cast, and instead fries her with a Lightning spell.
In the next episode, the Kvar moment is given some new awesomeness. As Kratos ends Kvar, he delivers the same line, but instead of three stabs, it's one stab that impales Kvar and comes out the other side, with plenty of blood. Awesome.
Oh, and just a bit later, the whole "we shouldn't be using Expheres" scene happens, and instead of the resolution that the game gives, the OVA shows that Lloyd and Genis went about battling the next Seal Guardian without their expheres. A feat that's flat out said to be impossible in-game.
The Fourth Episode is Full of these.
Kratos: "Sacred Powers, Cast thy Purifying Light upon these corrupt souls! JUDGMENT!" (Cue lasers from the heavens and countless Dragon riders being erased from existence)
The Remiel Fight. It starts with unison attack from Genis and Raine (albeit one that isn't in the game). Then Remiel blasts a hole in the side of the Tower of Salvation with a huge ass laser beam. Lloyd tanks that, then proceeds to fire off a massive Demon Fang of Epic Proportions, that sends Remiel into a tree, which shatters from the impact.
Lloyd, Genis, Sheena and Raine take on Yggdrasil to protect Colette while she's soulless. Yggdrasil ends the battle by using Time Stop.
Zelos takes out a dragon with Divine Judgement.
The party sans Colette and Zelos (Zelos having betrayed the party) fight off angels and finish them with Mystic Artes/Hi-Ougis. Genis using Indignation Judgement, Sheena summoning Luna, Presea using Critical Blade and Raine using Sacred Shine.
The OVA makes the entire final fight this for Mithos, as he gets to show off exactly what happens when you fight a four thousand year old Magic Knight who hasn't gone soft. The party barely manages to land a hit on him and even when he decides to finish things in a one-on-one swordfight against Lloyd, he only loses out of choice.
Give one to Colette who in a lot of the OVAs was a Damsel, was given the her time to shine when she blasted the Shit out of Yggdrasil with a Grand Cross. Bonus points for being one of the few attack to damage the guy, especially when you remember that he resists light elemental attacks, and give Regal the opening to triple kick the bastard flying across the room.