Maverick:
ANNABELLE BRANSFORD: But I thought you were a fast draw!
MAVERICK: I am! But I can’t hit shit!
And of course, from** Butch Cassidy and the Sundance Kid**:
Someone mentioned ‘Big Jake’ one of my favorites from there;
O’Brian: They tell me you killed two good men in a fair fight tonight. That true?
James McCandles: No, three; countin’ you.
O’Brian: Prove it.
Little Bill: I’ll see you in hell.
Munny: …yeah.
All in the delivery.
And the badassery at the end of For A Few Dollars More
The Colonel: Any trouble, boy?
Monco: No, old man. Thought I was having trouble with my adding. It’s all right now.
There’s tons of good lines in the Magnificent Seven:
“I admire your notion of fair odds, mister.”
"Generosity… that was my first mistake. I leave these people a little bit extra, and then they hire these men to make trouble. It shows you, sooner or later, you must answer for every good deed. "
"Chamlee: I’m sorry, friend, but there’ll be no funeral.
Henry: What?
Chamlee: Oh, the grave is dug and the defunct there is as ready as the embalmers ought to make him. But there’ll be no funeral.
Henry: What’s the matter? Didn’t I pay enough?
Chamlee: It’s not a question of money. For twenty dollars, I’d plant anybody with a hoop and a holler. But the funeral is off.
Henry: Now how do you like that. I want him buried, you want him buried and if he could sit up and talk, he’d second the motion. Now that’s as unanimous as you can get. "
Jebediah Nightlinger (Roscoe Lee Brown): You know in the late war between the states I served under an officer just like you.
Wil Andersen (John Wayne): Is that right?
Jebediah Nightlinger: As a mater of fact I shot that military gentlemen in the buttocks. Just outside Vicksburg.
Wil Andersen: I’d have hung ya.
Jebediah Nightlinger: They gave me a medal.
Wil Andersen: In my regiment, Mr. Nightlinger…I was known as Old Iron Pants. You might keep that in mind.
The Magnificent Seven again. One of O’Reilly’s groupies says he is ashamed of his father because he is a coward. O’Reilly bends the kid over his knee and gives him some quick swats on the bottom, then says, “Don’t you ever say that again about your fathers, because they are not cowards. You think I am brave because I carry a gun; well, your fathers are much braver because they carry responsibility, for you, your brothers, your sisters, and your mothers. And this responsibility is like a big rock that weighs a ton. It bends and it twists them until finally it buries them under the ground. And there’s nobody says they have to do this. They do it because they love you, and because they want to. I have never had this kind of courage.”
Makes me tear up every time I see it. Appaloosa, the only good line in fact. Ed Harris and Viggo Mortensen are a couple lawmen for hire after a bad guy. They catch up with him and two buddies. Five seconds later they’re down and wounded, the two buddies are down and dead, and the bad guy is riding off fast, relatively unscathed.
“Well, that went quick,”
“Yeah. Everybody could shoot.”
Open Range, Robert Duvall as Boss Spearman: “We got a warrant sworn for attempted murder for them that tried to kill the boy who’s laying over there at the Doc’s, trying to stay alive. Swore out another one for them that murdered the big fella you had in your cell. Only ours ain’t writ by no tin star, bought and paid for, Marshal. It’s writ by us, and we aim to enforce it.”
“I want every man in the Largo Militia to have a rifle”
“Whats the Largo militia”
"You aught to know,your in it.
Clint Eastwood to the Largo gun shop clerk.
“Short fuse”
-Duck You Sucker
From Rio Lobo, John Wayne (and it’s interesting for a man who is not considered a great actor, he should could deliver some great lines).
Sheriff ‘Blue Tom’ Hendricks: I should’ve taken you this morning!
Cord McNally: You should’a tried! (again, all in the delivery…Wayne makes it memorable)
Amelita: Turn around Sherriff, I want you to see who kills you!
Cord McNally: Did you get that fella at the gate?
Phillips: He’s at another gate now, lookin’ fer Saint Peter! (Jack Elam)
Wow! Blast from the past.
*Butch Cassidy: [interrupting] I think they’re in the trees up ahead.
Sundance Kid: In the bushes on the left.
Butch Cassidy: I’m telling you they’re in the trees up ahead.
Sundance Kid: You take the trees, I’ll take the bushes.
Percy Garris: Will you two beginners cut it out.
Butch Cassidy: Well, we’re just trying to spot an ambush, Mr. Garris.
Percy Garris: Morons. I’ve got morons on my team. Nobody is going to rob us going down the mountain. We have got no money going down the mountain. When we have got the money, on the way back, then you can sweat.*
It’s actually funnier in German:
*“Haben Sie ein Pferd für mich?”
“Nein, wir haben nur drei. Ein zu wenig.”
“Nein. Zwei zu viel!”*
I am shocked, absolutely shocked that High Noon is so underrepresented in this thread:
“You are a good-looking boy. You have beeg, broad shoulders. But your friend Kane, he is a man! Eet takes more than beeg, broad shoulders to make a man. You know sometheeng? I don’t theenk you will ever make eet!”
<spit> Bingo! (or Dammit!)
Percy Garris: I’m not crazy; I’m just colorful. That’s what happens when you live 10 years alone in Bolivia: you get colorful…<Blam>
Just about every line in that movie is a classic:
Sheriff Ray Bledsoe: You could at least have the decency to draw your guns.
Every time my brother and I would watch True Grit, Duvall would say his Mighty big talk for a one-eyed fat man line and my brother would holler Who you callin’ “one-eyed”? 
One from The Cowboys: Asa Watts (Bruce Dern): Take everything but the fire.
“You kill anyone today, Curly?”
“The day ain’t over yet.”
From Butch Cassidy and the Sundance Kid:
“I can’t swim.”
“Ha! Are you crazy? The fall will probably kill ya!”
True Grit has been underrepresented (since the opening post).
Mattie Ross:
Who’s the best Marshall they have?
Sheriff:
Bill Waters is the best tracker. The meanest one is Rooster Cogburn, a pitiless man, double tough, fear don’t enter into his thinking. I’d have to say L.T. Quinn is the straightest, he brings his prisoners in alive.
Mattie Ross:
Where would I find this Rooster?
Rooster Cogburn:
You can’t serve papers on a rat, baby sister. You gotta kill him or let him be.
Tombstone
Certainly not the best line ever, but it seems kind of relevant.
Henry Gatewood: [clutching valise with embezzled funds] I can’t get over the impertinence of that young lieutenant. I’ll make it warm for that shake-tail! I’ll report him to Washington - we pay taxes to the government and what do we get? Not even protection from the army! I don’t know what the government is coming to. Instead of protecting businessmen, it pokes its nose into business! Why, they’re even talking now about having bank examiners. As if we bankers don’t know how to run our own banks! Why, at home I have a letter from a popinjay official saying they were going to inspect my books. I have a slogan that should be blazoned on every newspaper in this country: America for the Americans! The government must not interfere with business! Reduce taxes! Our national debt is something shocking. Over one billion dollars a year! What this country needs is a businessman for president!
Ben Wade: Hey, you know you look kind of skinny.
Emmy: I feel skinny.
Ben Wade: That’s all right. I don’t mind a skinny girl - just so she has blue eyes to make up for it. You got blue eyes?
Emmy: Brown.
Ben Wade: That’s all right. They don’t have to be blue.
you use your tongue prettier than a twenty dollar whore.
Blazing Saddles
*John O’Hanlan: Harley, this is more money than I ever dreamed! Do-do-do you know what I can do with this much money?
Harley Sullivan: We passed some nice looking saloons.*
Jimmy Stewart and Henry Fonda, The Cheyenne Social Club