Twins

Arnold Schwarzenegger is looking for his brother Danny Devito in Houston.  He steals a cowboy's car (only temporarily). The man left his keys and very appropriate six shooter keychain in the ignition.

The Cleveland Show

Holt looses his car at a crooked river boat casino after symbolically betting his keys and steering wheel keychain.  The tic tac toe playing chicken takes his keys off the table.

The Apartment

I do not believe there is a keychain featured in this 1960 comedy BUT the poster has one prominently displayed.

Wonder Woman-DC Nation Short

In  this highly stylized animated short Wonder Woman is saving Steve Trevors from the other Amazons.  Her 70's styled muscle car has a distinct eagle keychain hanging from the steering column. 

The short is from "DC Nation" a series of shorts appearing on cartoon network featuring various superheroes.  This is from 2 of 3 for this little set.  It can be seen here: http://www.youtube.com/watch?v=sA-cQf2Gfpw

National Treasure: Book of Secrets

Riley (Nick Cage's partner) spends all his money he made off of the first national treasure they found, partly on a ferrari.  He finds that he cannot pay his taxes and his car is seized.  At the end of the movie they find the treasure and he receives his car back from the government as a thank you.  He finds the keys with signature ferrari keychain in the envelope with the letter of thanks.

The Last of Us

In the video game The Last of US the main character Ellie always wears a backpack which has a cute purple monster keychain attached to a zipper.  Since it is part of the character design it can be seen throughout the game.

Christine

Based on the novel by Stephen King the movie features a murderous car.  The keys that went to the car had a Victor plastic teardrop keychain.

Kill Bill Vol. 1

Uma Thurman plays the protagonist who after waking from a coma begins a quest for vengeance starting with those who abused her while she was in the coma.  She takes her revenge and her abuser's car which perfectly matches his keychain. 

White Collar (Front Man)

The main character Neil is trying to convince a receptionist to give him sensitive information.  He sees her vanity name plate keychain and calls her by her first name, "Kathy", to get into her good graces.

Johnny Test

In this kid's cartoon Johnny has two genius sisters who create wild inventions.  In this episode they create a key that can open any lock.  And the keychain attached to that key is a red x.

Cloud Atlas

At a hotel where one of Tom Hanks' characters is the clerk the rack of room keys can be seen.  The keychains appear to be wooden knobs.

The Next Three Days

Russell Crowe's chracter tries to break his wife out of prison.  While going through the metal detector at the prison his Saint Christopher keychain is placed in the bowl.

Batman: Year One

Throughout the movie three keychains can be seen.  One used by batman, one by a villain's henchman and one by Jim Gordon.  They are all just basic black fobs.

The Man Who Knew Too Little

Peter Gallagher's character shows off his keychain which appear to be a leather fob with metal medallion. 

Brewster's Millions (1945)

While hoping for good news on the phone Brewster's butler waves a rabbit's foot keychain over the phone for good luck

Total Recall (2012)

Colin Farrel plays quaid/hauser a lowly construction worker who everyday travels on the "fall" which transports him from one side of the earth to the other.  While in the center of the earth he is essentially weightless and a keychain can be seen floating around the room.  It appears to be a glass ball.

The Tourist

Johnny Depp checks into his hotel and the fancy red tasseled room keys can be seen behind the clerk and then handed to Depp.

Bottle Rocket

Owen and Luke Wilson's friend sneaks out of their room with the keys to his car stranding them at the motel.

Sin City

Marv, played by Mickey Rourke, takes a car and has the keys in his hands.  He comments on how the new cars all look the same.  The mercedes key has the logo on it and the electronic fob is attached.

In Time

In this sci fi action movie Justin Timberlake plays a wanted-by-the-police nouveau riche who is staying at fancy hotel.  He is receiving his room key with a fancy green tassel keychain attached. 

Macgruber

Macgruber comes out of retirement to return to the spy game and while he is retrieving his old car his white rabbit's foot keychain steals the spotlight.

Killer Elite

In this spy action movie Dominic Purcell's character is staying at a hotel and he receives his keys to his room in this scene. 

Don't Be a Menace to South Central While Drinking Your Juice in the Hood

Marlon Wayans plays an outrageous character with outrageous hair in this parody of hood movies.  His hair changes constantly throughout the film and in this scene has dice keychains in it.

Highlander

The Kurgan waits and plots to kill the Highlander in a seedy hotel.  The hotel desk clerk stands in front of the room keys and keychains

Paul

Simon Pegg and Nick Frost play sci fi nerds who are taking a road trip in an RV.  They have a star trek keychain as some nerd chic.  The ship is a klingon bird of prey.

Duke Nukem Forever

From the video game Duke Nukem Forever.  One of the weapons in the game is a remotely detonated pipe bomb.  To detonate the bomb Duke pulls out his car remote keychain and presses the button.

Captain America: The First Avenger

The villainous Red Skull is escaping his secret lab with his head scientist.  He gives the scientist the keys to fancy custom car.  His keychain is not coincidentally the Hydra symbol (his secret military group with advanced technology).  It must be due to his vanity. 

I Love You

A very lonely man played by Christopher Lambert finds his true love, it just happens to be a keychain.  The keychain says I love you.  From the obscure French art house movie I love You.

City of Lost Children

A keychain collection belonging to a character that collects things he finds under the water.  The movie is french and so are all the keychains.

Fallout 3

From the video game Fallout 3.  In your menu you have a list of the keys you find.  Of course, they are stored on your keychain.