Schwarzenegger is responsible for “I’ll be back,” yes, and it’s well known, but it’s only one.
On the other hand, Marlon Brando has to his credit:
“I coulda been a contender.”
“Let me make you an offer you can’t refuse.”
and
“STELLA!”
Clint Eastwood:
“Go ahead - make my day…”
“Do you feel lucky, punk?”
(Two movies, but the same character!)
Who’s got more, better iconic lines to their credit? Who is the King, or Queen, of iconic lines?
Al Pacino has to be a contender.
I don’t want to kill everyone, Tom. Just my enemies.
I know it was you, Fredo. You broke my heart. You broke my heart.
YOU’RE out of order! YOU’RE out of order! THE WHOLE TRIAL IS OUT OF ORDER! THEY’RE OUT OF ORDER!
Okay! You wanna play rough? Okay! Come say hello to my little friend.
I’d go with Clint - he’s got so many more than you listed:
“Buzzards gotta eat, same as worms.”
“It’s a hell of a thing, killing a man. Take away all he’s got, and all he’s ever gonna have.”
“In this world, there’s two kinds of people. Those with loaded guns and those who dig. You dig.”
“With all due respect sir, you’re beginning to bore the hell out of me.”
Aren’t **Humphrey Bogart’s **entire set of lines from **Casablanca **basically iconic? 
Kenneth Branagh and Mel Gibson have both played Hamlet, and he’s got a buttload of iconic lines.
Brando jumps to my mind first.
“The horror, the horror.”
“Your name is Kal-El. You are the only survivor of the planet Krypton.”
“You can act like a man!”
And those first two are from pretty minor roles.
Walken certainly has a number that are memorable if not iconic. There are enough to make The Walken Dead somewhat amusing.
Too many good ones to pick just one or two, but I’d go with Brando from memory. He had a field day in One Eyed Jacks (since he was the director!) with jewels like:
However, Clint is a solid second!
Bette Davis may be the Queen:
“Fasten your seatbelts. It’s going to be a bumpy night.”
“What a dump.”
“I’d love to kiss you, but I just washed my hair.”
“Oh Jerry, don’t let’s ask for the moon. We have the stars.”
Humphrey Bogart is my first thought, too. Casablanca:
I’m guessing there are famous lines from others, but these ones are pretty iconic.
“I’ll be back.”
“It’s not a tumor!”
“Hasta La Vista, baby.”
"Yeah, but they were all bad."
“Remember when I said I’d kill you last? I lied.”
“To crush your enemies, see them driven before you, and to hear the lamentation of their women!”
Samuel L Jackson
You’re absolutely right. Trumps Brando and Eastwood. I must have had a brain fart to overlook Sam and Walken.
This is my all-time favorite Ahnuld line. His earnestness as he speaks to Jamie Lee Curtis really sells it.
Groucho Marx
Gene Wilder. Thread over.
“Ze goggles. Zey do nothing!”
The Arnold quotes are great. The Gene Wilder quotes? I can’t believe I’m having to say this on the SDMB of all places, but cite?
Wilder has the unique quality of his quote being almost entirely in mime. Only the last word is spoken: “SEDAGIVE!?”
Harrison Ford, maybe?
–
Do Han Solo and Indiana Jones have any non-iconic lines?