I don’t know if this would be considered THE line or not, but…
“Hey she-bitch! Let’s go…” – Ash, Evil Dead
I love me some b-grade horror. 
well Casablanca seems to be popular. here’s my new favorite (that will change the next time I see it).
“seems like Captain Renault is becoming more open minded” Rick says to the girl that the captian is trying to blackmail, because the captain wanted to see both the girl and her husband.
Well, if THE line in Buckaroo Banzai is “Remember: Whereever you end up in Life, there you are” (IIRC)
Then some other great lines include:
“Yoyodyne, where the future begins…tomorrow”
“Laugh-a while you can, Monkey-boy!”
“Perfect Tommy, give her your jacket” “Why me?” “Because you’re Perfect” “…you’ve got a point there”
“Where are we going?” “PLANET 10!!” “When will we get there?” “SOON!!”
“John Big Bootie?” “Boo-tay, Big Boo-TAY!”
The list could go on for quite some time…
Nonetheless, Casablanca rules…
In The Stunt Man Steve Railsback is a fugitive from justice being hunted by two cops. At the beginning of the movie he is in a diner when the cops come in. Trying to act inconspicous, he starts playing pinball with a ball someone else has left behind. The cops sidle up to him, and one notices his high score.
Cop: You’re gonna win.
S.R.: Win what?
Cop: A free game.
S.R.: Just what I need. One more chance to lose.
Ghostbusters:
So? She’s a dog.
Yes, your honor, this man has no dick.
Ghostbusters, whaddayawant?
The Wizard of Oz:
Dorothy: I think he said “oil can.”
Scarecrow: Oil can what?
“No reason…I just like doing things like that…” - The Warriors
“Hey Mister! Can we have our ball back?” - A Hard Day’s Night
[sub]…ohh, man…I had a whole bunch of these a second ago…damn.[/sub]
Again from Casablanca
Renault: Rick, why did you come to Casablanca?
Rick Blaine: I came here for the waters.
Renault: The waters? Why, we’re in the middle of the desert.
Rick Blaine: I was misinformed.
From All About Eve
Addison DeWitt: I’m nobody’s fool; least of all, yours!
From The Women
Crystal Allen: There’s a word for you ladies, but it’s not used much in high society outside of a kennel.
From Army of Darkness
Sheila: I may be bad…but I feel gooood!
From The African Queen
Rose Sayer: Nature, Mr. Allnut, is what we are put in this world to rise above.
“Gentlemen! Gentlemen! There’s no fighting in the war room!” - President Merkin Muffley (the name’s hilarious in it’s own right) as played by the brilliant Peter Sellers in “Dr. Stranelove: Or How I Stopped Worrying & Learned to Love the Bomb”.
Also from Strangelove:
“Shoot! Shoot, you twit! With the gun! That’s what the bullets are for!” - Group Commander Lionel Mandrake (Sellers, again).
“Alright, mister. But you’re going to have to answer to the Coca Cola Corporation of America.” - Major Bat Guano (Keenan Wynn).
I have about a million.
Pee-Wee’s Big Adventure:
Francis Buxton: My father says I can have anything I want.
Pee-Wee: Good for you and your father.
Francis: So guess what I want?
Pee-Wee: A new brain!
Pee-Wee: Guess what?
Simone: What?
Pee-Wee: The Alamo doesn’t have a basement.
Simone: Oh, that’s too bad.
Pee-Wee: Yeah. They don’t teach you that in school. I guess it’s something you have to learn on your own.
South Park: Bigger, Longer, and Uncut:
Chef: Have you ever heard of the Emancipation Proclomation?
General: I don’t listen to hip-hop!
Willy Wonka and the Chocolate Factory:
Mr. Salt: Hey Wonka, what is this? A funhouse?
Wonka: Why? You having fun?
Mrs. Gloop (after her son has fallen into the Chocolate River): Do something!
Wonka: Help. Police. Murder.
Stanley Kubrick’s The Shining
Wendy: The weatherman says it’s going to snow tonight.
Jack: What do you want me to do about it?
What?! Behind the rabbit?!-Holy Grail
She hadda gooo bathroom-Annie
What about that time I found you naked with a bowl of jello?/Ice is nice! Lazlo buddy!/Ok, let’s take a step back. No, no, take a step forward. No, take a step back. Take a step forward. Now we’re cha-chaing-Real Genius
Peoples is Peoples-Muppets take Manhatten
The soft glow of electric sex/Sunofabitcheee! Bumpasses!-A Christmas Story
Laugh it up fuzzball-Star Wars
Did you say Allo? No, I said hello. Alright. Come in. Meet the Missus. Have a spot o tea-Labyrinth
It’s a stiff!Goonies
Fagabeefy!-Midnight Madness
Mick: It’s Mighty Joe BONG!
Pnub: I needs me Spinache!
-Idle Hands
Bankey: Which one is going to get to the hundred dollar bill first? The male-friendly lesbian, the man-hating dyke, Santa Claus, or the Easter bunny?
Holden: The man-hating lesbian.
Bankey: Good. Why?
Holden: I don’t know–
Bankey: BECAUSE THE OTHER THREE ARE FIGMENTS OF YOUR FUCKING IMAGINATION!
-Chasing Amy
Dante Hicks: What’s your encore? Do you, like, anally rape my mother while pouring sugar in my gas tank?
-Clerks
Army of Darkness–
“First you want to kiss me, then you want to kill me… blow!”
Ash
Full Metal Jacket–
“…What kind of a solder has born to kill written on their helmet and a peace sign on their jacket. What’s that supposed to be some kind of sick JOKE!”
“Sir, I think I was trying to suggest something about the duality of man sir!”
Private Joker and General (I’m sure I chopped that up pretty bad, especially the General’s line.)
Life of Brian–
“You are all Individuals!!”
<group> “YES! WE ARE ALL INDIVIDUALS!”
<lone voice> “I’m not!”
Brian and a large crowd (Ahh… so many lines from this movie!)
From ‘Ed Wood’
Preacher: “Do you reject Satan and all his evils?”
Bunny (Bill Murray), bored: “…sure.”
From “Spaceballs”
Dark Helmet: “Fuck! Even in the future nothiing works!”
Casablanca is one of my favorites and has some of the best lines in cinema from “Of all the gin joints…” to “Play it Sam…”, but my favorite is “The Major’s been shot… round up the usual suspects.”
“I breathe and drink plenty of water!”
“The police took the chicken. It was illegal chicken?”
“Where did the dogs go, Aurora? I ‘dint ax’ and they ‘dint’ say!”
- Seems Like Old Times
“There’s a tremendous build-up of guck on these windows!”
- Fletch
“Orange Whip? Orange Whip? …Three Orange Whips!”
“I’m Bob, and this is my place. We like both kinds of music: country AND western!” etc., etc., etc!
“We’re on a mission from God”
- Blues Bros.
“Etc., Etc., Etc.!”
- The King and I
“Why did you change your last name to Arizona? Would you buy furniture from ‘Unpainted Hoffheinz’?”
- Raising Arizona
“No coffee? Eat a peach, we’re running a cold camp!”
- John Wayne (the Western where he’s travelling with a group of boys - Slowhand Luke, maybe?)
"You boys gonna pull those pistols, or whistle “Dixie’?”
- Outlaw Josie Wales
“Do ya feel lucky, punk?”
- Dirty Harry
The defense rests!
- Jinx
“Back off, man. I’m a scientist!” -Ghostbusters
clint eastwood movie–“no, that doesn’t bother me. you know what really bothers me? you know what really makes me sick to my stomach? its watching you stuff your face with those hotdogs. nobody, i mean nobody puts ketchup on a hotdog.”
slapshot (almost too many to list, but here are a few favs)-- “you know, your son looks like a fag to me. you better get married again or (paraphrase) he’s gonna wind up with someones cock in his mouth quicker than…”
or
“and none of that stinkin root beer, either!”
or
“say that reminds me, i was coachin’ up in omaha when eddie schore sends me this kid who is a terrible masterbator…DAMN if he didn’t get deliberate penaltys so he could sit in the box, and well, you know…um,um,um,um (insert jacking off face here)…um,um,um,um…”
or
“that cunt is no good”
das boot-- the line about knitting nose hairs to ass hairs-- cant remember exactly how it goes now…
have a bunch more favorites, but i’m starting to hog the scene, baby!
Oh, and one that has to be the most ‘poetic’ that i can remember:
"No" - Marcel Marceau (the only ‘speaking’ part in Mel Brooks’ Silent Movie).
James Bond: "Do you expect me to talk, Goldfinger?
(Laser continues to cut through the metal table)
Goldfinger: “No, Mr. Bond, I expect you to die!”
The classic line in Aliens of course being “Get away from her, you bitch!”, my personal favorites are:
“We got tactical smart missiles, base plasma pulse rifles, RPGs, sonic electronic ball breakers! We got nukes, we got knives, we got sharp sticks…” - Hudson describing the marines’ armaments to Ripley
“They can bill me!” - Ripley making her decision to destroy the Company’s terra-forming complex.
I’m also always amused that the value of the Nostromos was $42 million. Seems mighty cheap for a star freighter.