The phrase appearing in the largest number of films...

[Croissant!]

...has to be "Let's get outta here". It can be whispered or mumbled, comedic or dramatic, hell, I'd bet it's even signed in Children of a Lesser God.

I noticed this about ten years ago when I watched three movies in a row where the phrase was used. Now I would safely bet that at least nine out of ten films I see use it, and now that I have pointed it out you will never be able to watch another movie without that line drilling into your recognition center.

You are welcome.

[Groucho]

"Hello"

[yohansen5b]

"the"

actually, i've heard the "factoid" that "let's get out of here" IS the most common phrase in movies. i think i heard it a few years ago, in fact.

[Croissant!]

"Hello", much like "Groucho", is a concept, not a phrase.

[devilshalo]

Bye

[John-In-VA]

I've got a bad feeling about this.

[Joe Molotov]

"Hello"

You had me at that.

[marty888]

<b>"What's <i>that</i> supposed to mean?"</b>

...or its alternative ..

<b>"What are you trying to say?"</b>

[PopcornTreeCt]

Bye

But never on the phone.

[DVD King]

One that I seem to hear a lot is "you were great back there".

[rich-y]

A favorite of the horror genre:

"Is someone there?"

Or one of the following variations:

"Hello, anyone home?"
"Hey, who's there?"

[SleepyW]

"Jack!" "Rose!"

Or did you mean in different movies? ;)

[Filmmaker]

The most used is also the easiest way of spotting weak screenwriting:

"You just don't get it, do you?"

Used 1,000,000,000,000+ times in modern cinema, and yet I challenge you to find a single instance in your lifetime when someone actually used that phrase in the real world.

[The Infidel]

"I love you."

[sauce07]

"I'm getting too old for this shit"

[DthRdrX]

I think 99% of the entire horror genre wins this one.

"I'll be right back"

[Mr. Cinema]

"You must be trippin" or "You trippin" or "I'm trippin" or....well, you get the idea.

[caiman]

"You must be trippin" or "You trippin" or "I'm trippin" or....well, you get the idea.

I'm proud to say that I've never seen a movie where this phrase is used.

[SFranke]

One that I seem to hear a lot is "you were great back there".
"You weren't so bad yourself."

[The Ferret]

Used 1,000,000,000,000+ times in modern cinema, and yet I challenge you to find a single instance in your lifetime when someone actually used that phrase in the real world.
Hey, my mom used to say that to me.

[Ayre]

Is he dead?

[Filmmaker]

Hey, my mom used to say that to me.

Then the script of her life is being written by a banal writer...

[Shannon Nutt]

"Be Careful!"

(Usually followed by the death of the character it's being said to)

[The Cow]

If pr0n movies count as films, then none of these are even close.... -wink-

[Charlie Goose]

These are the lines I've heard the absolute most in movies.

5) "How much for that rooster?"

4) "I think the botanist might be crazy."

3) "I dropped my kosher dill pickle!"

2) "It snowed the day we buried Uncle George. And that mule."

1) "Beans, beans, the musical fruit. The more you eat, the more you toot."

[whoopdido]

"Ah, Hell no"

[obscurelabel]

"Rosebud"

[Noojimbo]

Klaatu barada nikto

[mllefoo]

"Ah, Hell no"

No. That's the line most often said by Will Smith.

[Original Desmond]

fuck

[Fincher Fan]

"Dad, Nigga Charley's in the cornfield again!"

[RKillgore]

...has to be "Let's get outta here". It can be whispered or mumbled, comedic or dramatic, hell, I'd bet it's even signed in Children of a Lesser God.

I noticed this about ten years ago when I watched three movies in a row where the phrase was used. Now I would safely bet that at least nine out of ten films I see use it, and now that I have pointed it out you will never be able to watch another movie without that line drilling into your recognition center.

You are welcome.
My wife and I have the same tendancy to notice the also oft said line, "You should get some rest" or slight variation. Once you have a phrase in mind, of course you notice its frequency much more. And although it's much less frequent, we also get triggered on the absurdity of a person in a restaurant/bar who requests, "I'll have a beer", and is unquestioningly delivered one.

[pdinosaur]

whoa!

[stinkeye]

"Oh. My. GOD!!!!!"

Followed closely by:

"What the hell is that?"

[slop101]

...has to be "Let's get outta here"...

Actually it's "let's go!" There was a study that found that this was the most used pharse in all movies.

[mikewendt]

Gotta go with...

"Fuck you." or "Fuck that." or "Fuck this."

I think you see where I'm going with it...

[DVD King]

Another one: "I don't like the looks of this..."