Who can forget the scene in the movie where Doc Holliday, while dying from tuberculosis, skillfully shoots and kills feared Psycho for Hire Johny Ringo in a tense duel. This scene made the line "I'm your huckleberry" famous.
Better line: "Why, Johny Ringo, you look like someone just walked over your grave."
Or Doc Holiday defusing what would've been a brawl by twirling his drinking cup.
Or the line, "It looks like poker isn't your game. Maybe we should have a spelling contest."
Honestly, Doc Holliday's entire existence was just one long continuous Crowning Moment of Awesome. Aside from the above parts, there's also the scene where he has a gun pulled on an enemy as he's clearly fall-down drunk. "You're so drunk you're probably seein' double!" the enemy exclaims. Holliday then, without dropping his shot glass, pulls out a second gun and calmly retorts, "I have two guns, one for each of you." He then casually spins both guns mid-sentence, while holding the cup, in opposite directions.
After Curly Bill accidentally kills the sheriff, Wyatt staves off a lynch mob, only for Ike Clanton to turn up with several other Cowboys and demand that Wyatt let Curly Bill walk away. It escalates, until Wyatt has the barrel of his gun pressed against Ike's forehead, with the other Cowboys holding their guns on Wyatt.
Wyatt: The others might get me in a rush, but not before I turn your head into a canoe!
Cowboy: He's bluffing.
Ike: [clearly terrified] He's not bluffing. Back off. Back off!