Let's Get Out of Here

"So, why don't you make like a tree and get outta here?"

—Biff Tannen, Back to The Future

The good guys have just activated the self-destruct on the Big Bad's Kill Sat or carefully laid a time bomb in the center of the Elaborate Base. Or maybe they have advance warning for a natural disaster... Whatever the reason, it's time to beat a hasty retreat!

According to an official Trivial Pursuit question, this is the second most often used Stock Phrase in movies, right after "I love you."

Examples of Let's Get Out of Here include:

Anime and Manga

Said word for word in Tenchi Muyo! when Tenchi destroys Kargato's ship with everyone still inside.

Film

Who Framed Roger Rabbit?
The Movie of James and the Giant Peach.
One of the most memorable scenes in The Goonies. "Let's--" "get--" "out--" "of here!" "Like, NOW!"
Alien - Lambert saying these words after seeing the derelict space ship, before the alien infestation even begins. And in the sequel, Hicks yells out during the evacuation to Drake, who is hanging back, they they are leaving. It doesn't end well.
The Empire Strikes Back - Han Solo realizes that the "cave" in the asteroid in which they sought refuge was actually a giant space slug.
Pirates of the Caribbean 2: Will Turner sees Jack come running out of the jungle.... pursued by a horde of angry cannibals.

Literature

The Stock Phrase is used at least twice in The Tomorrow Series, each time followed by Lee (or Ellie) pointing out that it's a very commonly used movie line.

Live Action TV

Star Trek: The Original Series - Captain Kirk saying this after saving the entire natural timeline and future, at the cost of letting Edith Keeler die in "The City on the Edge of Forever". Actually comes up quite often over the course of the Star Trek franchise. Generally in the form of ordering a course setting and saying "Maximum Warp, Engage!". On one occasion, Captain Picard simply ordered the ship to warp on any course, when trying to escape from a Negative Space Wedgie.
M*A*S*H: When Trapper and Hawkeye realize they've cut the wrong wire in an unexploded bomb.
The cast of Red Dwarf were asked, "What does "smeg" mean?" by a young boy at an event where they were fielding questions from the audience. After a bit of throat-clearing, Robert Llewellyn looked at Craig Charles. Craig looked at Robert. ...and both got on their hands and knees, crawled behind their chairs and out behind the stage curtain, Robert glancing back to 'check' if anyone was following.

Video Games

Mass Effect 2 - Garrus Vakarian "needing some distance from this place" after seeking revenge against Sidonis on the Citadel.
- Also Shepard's "I've had enough of this colony" after getting chewed out by Kaidan/Ashley on Horizon.
The entire sinking tanker escape scene of the second Call of Duty 4: Modern Warfare mission, "Crew Expendable", is a nothing but this trope and Continue Your Mission, Dammit!.

Captain Price: On your feet, soldier! We are LEAVING!!

The first level of Metal Wolf Chaos, where you fight your out of the White House take off in Air Force One through the Washington Monument reflection pool and fly away.
Hostages you rescue in Counter-Strike also say this line after you get to them.

Western Animation

Practically Once an Episode on Scooby Doo.
Used on The Simpsons whenever someone gets injured and, rather than do the courageous thing and help the victim, the other characters run and leave him (or her) for dead. Was used in a non-injury related scene on "New Kid on the Block," where after Kearney (who's with fellow bully, Dolph) hits on Laura with "Hey, baby, how 'bout puttin' your finger in my ear!", Laura snaps back, "Well, I dunno. Your boyfriend looks like the jealous type." Kearney and Dolph are so shocked by the comeback, they shout, "Let's get outta here!"
William Shatner uses the line again in the Futurama episode "Where No Fan Has Gone Before", after Fry reminds the Original Series cast that the paradise they just left required them spending eternity with the universe's biggest Trekkie.