Salahadin: Nothing. (turns to walk away, looks back, and smiles in triumph) Everything.
Making the scene even more awesome is the conversation before that, when Salahadin promised that he would give safe passage to every Christian citizen of Jerusalem.
Balian: When the Christians took this city, they butchered every Muslim living within these walls.
Salahadin: I am not those men. I am Salahadin. Salahadin.
His emphasis on his name plays into this through a Bilingual Bonus, Salah a-din is actually a nickname meaning "Righteousness of the Faith" he sets himself apart from the Christians who first took Jerusalem by claiming his righteousness being of his faith, rather than because of it.
The king, Baldwin IV: "I am Jerusalem. And you, Reynald, will give me the kiss of peace."
Context makes this more of a brutal rebuke and thus more awesome: Baldwin is a leper since his youth; the hand he demands the villain kisses is covered with bleeding sores.
Made even more awesome that he beats the snot out of Reynald afterwards, even though it pushes his body too far.
His successor, Guy de Lusignan, gets one too: "I am Jerusalem. Assemble the army!!"
Except that Guy sounds pathetic and flacid when he says it, despite being drunk with power. When Baldwin says it the first time, he does so with the strength and confidence of a king who is worthy of his position. Despite being a weak and dying leper, Baldwin's strength of character makes Guy sound like an angry child.
Also, when Balian knights all the men at arms.
The final sequence with Salahadin, as he walks through the city for which he has united a people, fought a war, annihilated an army and humiliated a king. He walks on rose-petals into the Dome of the Rock as Crusader banners fall from the ceiling. And then his servants and soldiers all leave, the doors close behind him - and he marks his victory by bowing in silent prayer.
When Salahadin waltzes around the city of Jerusalem, he stops in his tracks once he sees a Christian cross on the floor. He picks it up and respectfully places it back on its altar. According to some news reports, movie audiences in the Middle East gave this scene a standing ovation.
From the extended edition - the Balian vs Guy duel ends with a classic Sword over Head. Guy, injured and on his knees, demands a finishing blow. Instead...
Balian: When you rise again - if you rise - rise a knight.
"SIIILLLEEEEEEENNNNCE!" Because Tiberius can be a badass without ever pulling out his sword.
Saladin slashing Jerk Ass Reynald's throat after taking a cup of water meant for Guy.
"A king does not kill a king. Were you not close enough to a great king, to learn by his example?"
The entire siege of Jerusalem at the end. The city's badly outnumbered defenders hold off the Saracens for three days thanks to Balian's strategy and the morale boost given by knighting every soldier within the walls.
Saladin shutting down the annoyed mullah who comes to him demanding to know why he did not attack Kerak.
Mullah: (after demanding to know why Saladin has retreated from a fight) If you think that way, you will not be king for long.
Saladin's Badass Boast also carries with it a very palpable Real Life subtext. Upon Saladin's death, the previously-united and enlightened nations under Islam quickly devolved into infighting and squabbling, leading to the rise of Fundamentalism that has tainted the image of Islam in the modern world.
In the fight between Godfrey's men and the Sheriff's forces the German Knight goes down pretty quickly with an arrow to the throat. This doesn't stop him. He gets back up and proceeds slaughter a few of the Sheriff's men before another two arrows send him to the ground