In the first episode: After the Jokerz chase Terry to Wayne Manor and see Bruce Wayne, the gang's leader threatens Wayne with "Who do you think you're talking to, old man? We're the Jokerz!" His reply? "Sure you are."
Also when Terry and Bruce tag team together in the first episode, and proceed to kick the gang's booties all over the place!
Bonus points for Old Bruce pulling off the legendary Offhand Backhand with his cane.
Earlier in that episode, when the Jokerz trash the outside of the dance club they (Terry and fellow classmates) were all waiting in line to get in, Terry steps up and kicks their tails all around! He does a pretty good job taking on the 6-7 of them all on his own, before reinforcements arrive, and he's forced to make a hasty exit, that leads him to Wayne Manor — thus ensuing the beatdown listed above.
"Very good then, Mr McGinnis. Welcome to my world." Tinge of Nightmare Fuel there too; as the Danny Elfman minor chords start strumming, you realise Terry has no idea what he's getting into.
Terry interrupts Nelson bullying Willie Watt:
Terry: Lay off him, Nash. Don't you have something better to do? Nelson: You think I'm afraid of you, McGinnis? Terry: (lifts his eyebrow and smirks) I dunno. Are you? (Nelson actually backs down)
Terry reveals his impressive knowledge of Talia al Ghul, her role in helping out Bruce in the Near Apocalypse of 09, what she's currently doing with her life and where she lives, shocking even Bruce. Terry takes being Batman seriously.
Terry and a rejuvenated Bruce Wayne are faced with a group of goons charging at them. Terry gives the "Go right ahead," gesture. Cue coordinated ass kicking set to the Batman: The Animated Series theme. Will Friedle has said this is one of his favorite scenes in the series.
From that same episode: When Bruce is held prisoner by Ra's Al Ghul and learns that the villain disposed of his own daughter's consciousness to live on her body and is about to transfer into Wayne's. Despite the dire peril at angering the villain in this situation, the old man lets loose his contempt regardless: "You don't cheat death, you whimper in fear of it!" And when Ra's slaps him for that insult, Wayne jabs, "And you hit like a girl!"
Terry's battle with Ra's also qualifies; Ra's is one of the deadliest warriors on the planet and Terry was able to not only hold his own but win.
Derek Powers firmly establishes how vile he is with one of the most awesome comebacks in animated history. He just sounds so annoyed, more than anything:
Terry's response? "Sorry, that's all you get." He did know, and that was why he's (becoming) Batman.
The Call, from start to finish. Starting with Micron stopping the monorail solo, followed by Batman vs Inque in Gotham, who traps a man to hold him hostage against Batman. The man turns out to be Superman, who just says he'll take it from there and by spinning around with his super speed, he scatters Inque all over the place. Batman is then recruited into the Justice League Unlimited to find a traitor and thanks to a bit of work on Bruce's part, figures out that Superman is the traitor because of a alien called Starro that's controlling him, who plans to take over the entire world with its replicas, starting with the JLU except for Batman, who escapes thanks to a flash bomb and Bruce sending him the Batmobile.
This is followed by Starro-Superman catching up with the Batplane, which is traveling at Mach 3, while the theme music from his previous show plays in a sinister key... and not streamlining at all, but floating upright. As seen here.
The Batmobile crashes and through some quick thinking, Batman hits the Starro with an electric charge that makes it lose control of Superman, who gets it off himself and then through heat vision and electrocuted Batarangs, Superman and Batman get all of the Starros off of the other JLU members and then send the Starros back to their homeworld.
In a similar note to the moment listed above, when Superman reveals himself what music plays? The classic refrain from Superman: The Animated Series. Combined with Terry's awed reaction (and his later dubbing of Supes as 'the greatest hero who ever lived'), you feel the due respect the Man of Steel is owed.
Terry's first appearance when he kicked the crap outta that Jokerz dude... This was before he donned the cowl.
This also happened in the first episode of Season 2, Splicers. Just like in the first episode of Season 1, two of geneticist Able Cuvier's groupies- King Cobra and Ramrod- decide to flaunt their "genetic superiority" by terrorizing innocent Gothamites on one of the city's bullet-trains after a news bulletin displayed D.A. Young pledging to ban splicing as illegal and unnatural. However, it just so happens that Terry is on the train and (just like he did with Jokerz), decides to show them just how wrong they are by effortlessly wiping the floor with both of them. Not bad for a "norm."
Terry: So, will you petting-zoo rejects be needing a doctor? Or a vet?
When Terry is captured by Inque in "Disappearing Inque", it's left to Bruce to show up in an attempt to save him. He gets captured by Inque and slowly crushed... at which point his overcoat bursts apart, revealing a Bat-mech suit. Two things make this especially brilliant:
Bruce had pointed out the suit earlier, saying he couldn't use the thing because it aggravated his heart condition.
Terry's reaction is initially a horrified "Oh no..." and renewed struggling against his chains. Then Bruce punches Inque across the entire stadium. Terry just watches her fly in utter awe.
One more, though it's mostly icing: during The Reveal of the powered armor, the soundtrack goes into an iconic bit of the original BTAStheme music. During the entire time Bruce is fighting, a remix is playing with a full orchestra, an electric guitar and horns.
In "Where's Terry", Bruce and Max team up to find a lost Terry. To this end, they follow a gang of T's who have Terry's empty backpack. The thugs try to mug Wayne, and are almost successful in a five-to-one battle. Then Max lowers that to three-to-one, and the remaining three promptly get beat down. Bruce turns to the guy carrying the backpack and tells Max to leave the room. A minute later Bruce has the information he needs, and is completely confident he was not misled. It's not just the JLU episode which proves how awesome an interrogator Old!Bruce is.
From the same episode... when Shriek had Terry and the little boy he just saved cornered at a cliff-like drop in the sewers. "All that for nothing, all that effort wasted. At least it gives me the pleasure of finishing you off myself." Then out of nowhere comes Bruce, "Why do they always talk so much?" Whacks Shriek only two times in the head with his cane, looks at Terry before leaving, "I just happened to be in the neighborhood." Dang you Bruce! Why must you be so freaking awesome!?
Another moment of Old!Bruce awesome comes when he's attacked by Payback and succeeds in holding him off long enough for Terry to get there.
Bruce: Mm-hmm. And what are you?
Payback: I'm your worst nightmare!
Bruce: You have no idea what my nightmares are like.
Terry going up against the Batsuit while it was being controlled by an insane AI. And beating it with his own smarts and a bit of MacGyvering.
To make it better, Terry only had two pieces of Bat-memorabilia on him during the fight: the belt off of the original Bat-suit, (Given to him by Bruce himself) and Nightwing's mask.
Bruce even tried one last time to scare Terry out of it, but Terry doesn't sway at all. Bruce just gives a small smile, as if that moment he truly accepted Terry as a worthy successor.
Commissioner Barbara Gordon knocks the sword out of the hand of Curare (who was going after her husband) with one of Terry's Batarangs. When it goes flying back into her hand, you see a smug grin on the old Batgirl's face that clearly says, "Oh yeah, I still got it!"
Terry: You should have seen her Bruce, she sure swings a mean batarang.
Bruce: (grins) She always did.
The fact that Terry stole Bruce's own batsuit, from right under him, without him HEARING TERRY come in at all (considering this man is known for a certain backhand and defiance of the laws of science)... pretty dang impressive!
In "Heroes", The Terrific Trio fighting off an assault by the army in their own tower. They're forced to run for it due to the army Zerg Rushing them, but with all things considered, they put up a pretty good fight.
From "Curse of the Kobra: Part II" which doubles as a Crowning Moment of Heartwarming, Max has been kidnapped by the Kobra cult to be their queen and Terry is desperate to find her despite his injuries, including four cracked ribs that hurt when he breathes. When he and Bruce finally locate her whereabouts, there's this exchange:
Bruce: What about your breathing problem?
Terry: (pulls on the mask) I'll breathe on the weekend.
Max giving an able assist to Terry in her first appearance, particularly when he first tells her to run, which she interprets as tackling one of the Jokerz.
During "Mind Games," Terry fights a mysterious old man (later revealed to be Edgar Mandragora) who has incredible telekinetic and telepathic powers. Not only is he stuck in an illusion for the whole fight, he's fighting an enemy with supernatural powers. That it was set to some rocking music doesn't hurt at all. Watch it here.
When the police believe Batman has killed Mad Stan, they show that they aren't as incompetent under Barbara Gordon's command. It was looking really grim for Terry until Spellbinder was pulled out of hiding.
Said suit includes a hologram function that works better than Spellbinder's own illusion-based tech, and, as it was a suit Lord Batman was building designed to combat Lord Superman, it comes equipped with synthetic Kryptonite mode.
Also from the Justice Lords arc and involving Lord Batman's Beyond suit, Terry fools everyone into thinking Lord Superman had killed him by using the suit's hologram projector to disguise a log as himself. He proceeds to "come back from the dead", rescue T, conspire with that timeline's Dick Grayson, and returns to his original timeline to kick Lord Superman's butt, Big Damn Heroes style.
To save Terry from Rewire, Dick overpowers Rewire, rips an electrical device from his heart, says goodbye to Babs, and thrusts the device at Rewire, resulting in a massive electrical charge that knocks Rewire out and seemingly kills Dick. Dick regains consciousness a few minutes later.
In one of the side comics for Batman Beyond, Barbara reveals to Terry that her dose of fear gas she received in "Over the Edge" occasionally causes PTSD episodes in her every couple of years. The most recent incident happens during an attempt by the two to retrieve a kidnapped young girl, resulting in her having a near mental breakdown.
Terry: Commissioner. Commissioner Gordon. Barbara. It's me. Batman. You remember, I'm here to help you. Nothing can happen to you as long as Batman's with you. Isn't that what you said? You always felt safe when Batman was near. Barbara: You're not him, you know. You'll never be him. Terry: ... [grabs her by the collar] Now you listen. You may be afraid of you-don't-even-know-what, but I don't care. Be more afraid of me. Be more afraid of what's going to happen to that little girl if you don't do your job and find out where she is. Capisce?
Crosses over with Heartwarming Moment after she's recovered from her episode. While she states that she wasn't wrong in that he would never be exactly like Bruce, she makes it clear that he truly embodies everything good about Batman.
One comic ("Return") shows Batman facing Blight, whilst Bruce Wayne has a meeting with the board members and Paxton. On one hand, Terry destroys the functions on Blight's suit during a fight, causing the radiation in the latter's body to tear itself apart. On the other hand, you have Bruce Wayne who diplomatically ousts Paxton from his company.
Even cooler: It's essentially Bruce Wayne and Son defeating Derek Powers and Son, back to back.