Batman's first scene where he takes out two muggers. Believe it or not, there was a huge outcry when Michael Keaton was cast, due to his status as a comedic actor. This scene put any of those doubts to bed.
Mugger: (hysterically, being dangled over the side of a building) DON'T KILL ME, MAN! DON'T KILL ME!
Batman: I'm not going to kill you. I want you to do me a favour. I want you to tell all your friends about me.
During the climax, Batman is in the Batwing gunning directly for the Joker, who is standing defiantly in the middle of a deserted street. Batman lets loose with a barrage of machine-gun fire and missiles, which the Joker calmly stands through whilst they explode around him. The Joker then produces a verylong-barrelled revolver from his jacket and, with one shot, manages to shoot the Batwing out of the sky.
Joker: (quietly, as Batman opens fire around him) Come on, you gruesome son-of-a-bitch. Come to me!
That scene was ripped shot-for-shot from Patton, making George an even bigger badass.
The swelling climax of Danny Elfman's score for the first film turns reading a letter, turning on a light, and standing around into something awesome.
Gordon: He gave us a signal!
In fact, anyone who was sitting in a theater during the first run still get chills over the opening credits. The low, thrumming horns immediately signaled, "Yeah, there's no Shark Repellent Bat Spray in this movie."
Don't forget in Batman the entrance in which Batman breaks through the glass, grabs the girl and just zips out, leaving Joker to wonder "Where Does He Get All Those Wonderful Toys?".
The script has a second part to that last bit of dialogue, said from the Joker to his henchmen: "Well don't just stand there, GO ASK HIM!"
The scene where Joker sits on Grissom's desk overlooking the city.
Joker: Gotham City... always brings a smile to my face. (notices a blood-splattered newspaper on the desk) "Winged Freak Terrorizes"? Wait 'til they get a load ofme!
Say what you will about how foolish Knox may act. However, when he put on the mask, took a baseball bat and was attempting to drive the Joker's goons away, that was really awesome on his part. Not really effective to stop the whole disaster, but the very fact that he had the balls to do it and managed to make at least one poison gas-spreading balloon take off makes it cool.
Bruce had enough with Vicki yelling at him for shunning her, because he needed to explain himself.
Bruce: You're a real nice girl and I like you a lot. But for right now... shut up!
The scene where Bruce says, "Let's get nuts". While unintentionally amusing, you've got to admit it takes a lot of balls to stand up to the Joker and challenge him to a fight with nothing but a fireplace poker — and as it turns out, a silver tea tray hidden under his shirt — whilst Joker and his goons have guns.
"Excuse me. You ever dance with the devil in the pale moonlight?" Said to the Joker by Batman, who then punches him face-first into a church bell, and grabs the murderous clown with full intent to end him. Then when Joker attempts to get on his high horse about how he caused Jack's own transformation, Batman responds with a Kirk Summation and an even more vicious beating, leaving the formerly-untouchable mob boss quaking with fear.
Joker: (stammering in fear) H-hey, bat-brain, I mean, I was a kid when I killed your parents. I mean, I say "I made you", you gotta say "you made me". I mean, how childish can you get? (puts on some glasses) You wouldn't hit a guy with glasses, huh...?
The entire sequence. Many comic fans argue that Batman would never kill, but at least in this rendition, there are known factors to be taken account here. He just found out Joker murdered his parents, which in turn made him become Batman. During his first stints he drops Jack into the chemical vat, making him the Joker. Which in turn makes Batman partially responsible for every death the Joker has dealt. When it all goes full circle, not only does he break his one rule while calm, he also uses various firearms on his Batmobile and Batwing to do the job. You'd have to do something really bad to piss Batman off enough to subvert his earlier morals. Especially when crashing his plane will do nothing more than slow him down.
Credit must also be given to the final one of Joker's goons, who solidly overpowers Batman in a straight fistfight until being thrown off the belltower. The Joker certainly got his money's worth from him.
The creative and oh-so satisfying way in which Batman takes down the Joker for good, from a very disadvantageous position. When the Joker's helicopter arrives and he climbs onto its rope ladder to make his escape, Batman uses his Grappling-Hook Pistol to fire a cable around Joker's leg and a nearby stone gargoyle. The helicopter takes off, and the weight of the gargoyle slowly (and painfully) drags Joker off the rope ladder; sending the monstrous clown plummeting to his death far below. Joker's own ironic closing taunt and how he immediately goes from triumphant to flat-out terrified in the face of death makes it even better.
Jack Nicholson's high-pitched giggles after seeing his face for the first time in the mirror absolutely nail the Joker laugh, making him both awesome and terrifying right off the bat.
The Batmobile. Right off the bat, it really proved itself to be one of theundisputed coolest cars in film history; especially when it near single-handedly destroys Joker's hideout and Smilex production line at Axis Chemicals. It smashes through heavy walls and tears through everything and everyone that tries to stop it with a huge assortment of weapons — including oil slicks, a pair of Browning machine guns, disc launchers, and chassis-mounted shinbreakers — eventually getting to the core of the factory, blowing it up with an enormous bomb, and racing out of the inferno almost completely unscathed.
Even though some of its badassery can be undermined by missing the Joker and getting taken down with a single shot from the Clown Prince of Crime, the Batwing is another awesome vehicle, largely due to its cockpit and functions resembling an X-Wing, and for how Batman uses it to end the parade massacre by catching all the balloons and releasing them away from Gotham City, before triumphantly flying it above the clouds and blocking the full moon, making it look like a giant natural Bat-Symbol◊ in one of the most iconic shots of the movie.
As much as Pat Hingle's Commissioner Gordon increasingly becomes The Load across this take on Batman, his appearance at Axis Chemicals in this film basically confirms he's the good cop he should be; he and a squad assume control of the police operation, Gordon wrestling a megaphone from Corrupt Cop Eckhart and informing him he's in charge, not Carl Grissom.
Gordon: He gave us a signal!
