Movies are so full of good quotes, it's just hard to find a place to start! I know someone's probably already started a thread like this one, but I just had to do it anyway! :)
So, what are the most immortal lines ever from a movie? How about these:

I'm gonna make him an offer he can't refuse" - The Godfather

"You talkin' to me?" - The Taxi Driver (with Robert DeNiro)

"Are you feeling lucky, punk?" - Dirty Harry

"You're good kid, real' good, but as long as I'm around you'll always be second best" - The Cincennati Kid

"Here's looking at you, kid" - Casablanca

"Mother! Oh God, Mother! Blood! Blood!" - Psycho, one of my favourites
*
...just a few thoughts.

"Run Forrest, Run!"

"Astalavista baby"

- "I even found myself driving by convienence stores...that weren't on the way home" - Nicholas Case, Raising Arizona.

- "Ya know, for kids" - Tim Robbins, The Hudsucker Proxy.

- "I'll be back" - Arnold Schwartzenegger, Terminator

- "Please, just for one day, find me irresistible" - Julia Roberts, My Best Friend's Wedding.

Many more I cannot think of now, of course. :)

Mine arn't really immortal, but some of my favorites anyway.

Hey Chris, perhaps you're right...I think the subject line should be changed to something like "Your favourite movie lines" or "Unforgettable movie lines", it works a lot better :)

My God! It's full of stars!

Give my creation liiiiffe -Frankenstein!!

Whud the hell are you? -Predator

HahahaHaHaHAHAHA! -Predator

We don't have ticks anyway. We're American. -Titanic :)

Show me the money! Show me the munnny! :)

I was porn a poor black child.. -Steve Martin

Speaking of Predator(a lil vulgar) but i loved when Arnold said

"You are one ugly mutha F***a"

"I have a head for business and a bod for sin. Is there anything wrong with that?" - Working Girl

"We've gone plaid!!" - Spaceballs

"If I forget to tell you later, I had a really good time tonight." - Pretty Woman

"Greed is good. Greed works." - Wall Steet

"There can be only one." - Highlander

"All I need to find you, Louis, is to follow the corpses of rats." - Interview With The Vampire

"Back and to the left." - JFK

"I rule!!" - American Beauty

"Insanity runs in my family. It practically gallops." - Cary Grant, Arsenic and Old Lace.

I don't know how 'immortal' some of these are, but they're favorites:

"Hooo-ah!" - Al Pacino in "Scent of a Woman"

"They're called boobs, Ed." Julia Roberts in "Erin Brockovich"

"Mr. Hunt, this isn't mission difficult, it's mission impossible. "Difficult" should be a walk in the park for you." - Anthony Hopkins in "Mission Impossible 2"

"I do wish we could chat longer, but I'm having an old friend for dinner." - Anthony Hopkins in "Silence of the Lambs"

"There are many things my father taught me here in this room. He taught me: keep your friends close, but your enemies closer." - Al Pacino in "The Godfather: Part II"

"She's prejudiced against Italians. Can you believe that? In this day and age, a Jew broad, prejudiced against Italians!" - Joe Pesci in "Goodfellas"

"You make me want to be a better man." - Jack Nicholson in "As Good as it Gets"

"You can't handle the truth!" - Jack Nicholson in "A Few Good Men"

"He had a business card and everything." "A business card? Wow, that's some f**king accomplishment." - Joe Viterelli and Robert De Niro in "Analyze This"

"Are you trying to look unattractive?" "Yes." "Well, congratulations. You've succeded admirably." - Annette Bening and Thora Birch in "American Beauty"

"Sometimes there's so much beauty in the world I feel like I can't take it, like my heart's going to cave in." - Wes Bentley in "American Beauty"

"Anyone who spends a significant amount of time with me finds me disagreeable." - Morgan Freeman in "Se7en"

"Look, but don't touch. Touch, but don't taste. Taste, but don't swallow." (on God) - Al Pacino in "The Devil's Advocate"

"When in doubt: f**k." - Al Pacino in "Scent of a Woman"

"There is nothing like the sight of an amputated spirit. There is no prosthesis for that." - Al Pacino in "Scent of a Woman"

"That's good, because I take no pleasure in taking life if it's from a person who doesn't care about it." - Gary Oldman in "The Professional"

"I see dead people." - Haley Joel Osment in "The Sixth Sense"

Heh. Now I'm tired.

Crash, I gotta admit, you've definitely got a taste for movies (at least very similar to mine) :) Scent of a Woman is absolutely one of my all time favourites! I can't believe I forgot Anothony Hopkins from Scilence of the Lambs...

Like you said, Hooo-ah!

I'm very particular about my films. :) Scent of a Woman is one of my absolute favorites, too! It's one of those movies I can watch straight through without fastforwarding through anything. Al Pacino's performance is just magical.

And forget Silence of the Lambs? Are you crazy?

-"I'll make him an offer he can't refuse" Godfather Part I (AFAIK).

-"I feel the need...the need for Speed" Top Gun.

-"Dave? I am afraid I can't let you do this" 2001.

-"Any of you pricks move...and I'll execute every moth** f***** last one of ya" Pulp Fiction.

Cheers!

"I love the smell of nepalm in the morning." -- Apocalypse Now

hehe I forgot this one...it's a must! :)

Cheers!

"I am your father" -- Darth Vader, Star Wars: The Empire Strikes Back. No, he doesn't say "Luke, I am your father," even though everyone thinks he does.

You can't fight in here, this is the War Room!- Dr. Strangelove

"Close, Riggs? Close as a lingerie shop without a front window." -- Rene Russo, "Lethal Weapon 3"

Not immortal, but funny.

"Woah." -- Keanu Reeves, "The Matrix"

"I know Kung Fu." -- Keanu Reeves, "The Matrix"

"Your going to need a bigger boat."- Jaws

"Frankly, Scarlett, I don't give a damn." Gone With the Wind

"I'm the king of the world!" Titanic

"Aaaaaaahh!" Home Alone