The Shelf of Movie Languishment

The movie is finished. The cast and crew have been paid, postproduction is done, all it needs is an advertising campaign and to be sent to the theaters. Except it isn't, at least not at the speed most of its completed brethren do.

The act of being 'shelved' is one of the oddities of the movie business. There are many reasons that a completed movie is set aside; a matter of timing, dissatisfaction with the result, corporate restructuring, etc. It can last anywhere from a couple months to forever.

See Executive Meddling and Troubled Production (a major cause of this); compare Keep Circulating the Tapes (where the rights holders don't release copies for purchase after broadcast) and Ashcan Copy (where the work was produced only to maintain the rights and was never intended for publication).

9/11

 * A surprisingly large and recognizable number of media were delayed, modified, and/or never released due to 9/11. Rather than distributing them to their media slots, anything affected by 9/11 should be noted here. A Wikipedia page with a comprehensive list is here.
 * Grand Theft Auto III and Metal Gear Solid 2: Sons of Liberty were technically completed around that time, but had their release dates pushed back so that potentially insensitive material could be edited out. With GTA, it was the NYPD coloring of the police cars, and with MGS, it was the scene where the Statue of Liberty gets destroyed.
 * The movie Collateral Damage was supposed to be released in October 2001 but was shelved for four months due to it terrorism theme while they re-edited the movie and created a new trailer.
 * Big Trouble and Bad Company were both delayed for the same reason.
 * View From The Top was supposed to be released in late 2001, but was delayed until 2003 due to studios being uncomfortable releasing a film that made fun of flight attendants so soon after 9/11.
 * The premiere of the anime version of Full Metal Panic! was pushed to 2002 due to the 9/11 attacks and the main character's backstory of being a mercenary in Afghanistan, which was renamed to "Helmajistan".
 * A teaser trailer for the first Spider-Man film had a web stretched between the two main towers of the World Trade Center, the movie poster also showed the WTC, both the teaser and the poster were quickly re-called after 9/11.

Film

 * Blue Sky. Completed in 1990, not released until 1994 due to the bankruptcy of Orion Pictures.
 * Ditto for the film adaption of Car 54, Where Are You?
 * The Charlie Chaplin film Limelight was pulled from distribution after he was denied re-admittance to the US for allegedly having communist sympathies. Filmed in 1952, finally released in 1972.
 * Plan 9 from Outer Space was completed in 1956, but couldn't find a distributor until 1959. That is nowhere near as bad as what happened to Ed Wood's follow-up, Night of the Ghouls, which didn't see the light of day until 1987. The reason? Ed couldn't pay to have the film developed and it was withheld by the lab.
 * Miramax had a glut of films finished in the early 2000s and delayed releasing some of them for several years. Many made nowhere near the money production had cost.
 * The Great Raid was one of these.
 * Underclassman was another.
 * Dimension films had similar problems, Texas Rangers and My Boss's Daughter(changed from original title "The Guests") were both shelved for over a year, the former only got a limited release, though the latter managed to do decent business.
 * Yuri Kara's movie Master And Margarita was a victim of the shelf for some decades, being only recently released.
 * Me and Orson Welles premiered to great acclaim at the 2008 Toronto Film Festival, but was unable to secure a distributor despite the considerble buzz and the fact that they had Zac Efron and Claire Danes as the stars. It was eventually released to perhaps a dozen theatres nationwide in November 2009 and almost promptly forgotten (it's release on DVD was even more delayed). Many fans claim that this piss-poor release strategy ended up robbing co-star Christian McKay of a well-deserved Oscar nomination for his performance as Orson Welles.
 * The Nutcracker in 3D was filmed in 2007, but not released until 2010. The delay was partly to allow for the afterthought of converting it into a 3D Movie.
 * Red Tails suffered in Development Hell from the 80's until 2007, and even after it was in the can and ready to go in 2010 it took another couple years before George Lucas could find a distributor willing to take it. The reason given for both the decades long hell and this trope was that the cast was mostly black.
 * The classic Film Noir The Big Sleep was completed in 1944, but the studio shelved it in order to get through their backlog of war movies before WWII ended. This proved to be a very good thing. Before it was released in 1946, scenes were added to capitalize further on the obvious on-screen chemistry of Humphrey Bogart and Lauren Bacall.
 * The remake of Red Dawn was mostly complete in 2010, but got shelved due to MGM going bankrupt. After the studio solved its financial problems - and a Recut happened to replace the Chinese villains with North Koreans - it got a November 2012 release date.
 * The Cabin in the Woods was also a victim of MGM. It was finished in 2009, but MGM delayed to do a 3-D conversion, but their bankruptcy forced them to abandon those plans. The film finally saw the light of day in April 2012 and was critically acclaimed to boot.
 * All About Steve was shot in 2007, but only got released 2 years later. (in the meantime, star Bradley Cooper made a name for himself)
 * Lucky You was shot in 2005 and not released until 2007, where it flopped at the box-office.
 * Two of Eddie Murphy's films fall into this category, The Adventures of Pluto Nash was completed in 2000 but not released until 2002, A Thousand Words wrapped up in 2008 but was delayed until 2011, after some parts of the ending were re-shot, then it got delayed until 2012, where it promptly flopped and was quickly forgotten.
 * Bucky Larson Born To Be A Star was completed in 2009 but not released until 2011 due to poor test screenings and the distributor having little faith in it.
 * The live-action version Grave of the Fireflies was shown to critical acclaim in many film festival circuits in 2008, but didn't get any kind of theatrical release until 2011.
 * Two of Miley Cyrus's films, LOL and So Undercover were both delayed from their 2011 release dates and are currently scheduled to be released in May and June 2012 respectively.
 * The Catherine Zeta-Jones film Rebound was completed in 2009 and was released to theaters in almost every country except the U.S. then it finally got released to Amazon Instant Video in February 2012.
 * Repo Men was finished in 2008 but not released until 2010.
 * Phone Booth was supposed to be released in 2002, but was delayed until 2003 because of the Beltway Snipers rampage.
 * Take Me Home Tonight was finished in 2007, but was delayed until 2011 due to the studio being uncomfortable with the scenes depicting drug use.
 * Fanboys went through a legendary delay, it was finished in 2007, but delayed because the Weinsteins thought the cancer subplot in the film would make it less profitable, so they hired another director to re-shoot certain scenes, though Kyle Masterson eventually prevailed and managed to get the film a limited theatrical release in 2009 with the subplot intact.
 * The Sarah Michelle Gellar film Posession (which was a remake of the South Korean film Addicted) was filmed in 2007 and scheduled for a theatrical release in winter 2008, but the film's distribution company ended up going backrupt, which caused the release date to get pushed back nearly a dozen times until it was finally released Direct to Video in March 2010(and given the lackluster reviews, it's probably for the best)
 * Trick 'r Treat was supposed to get a theatrical release in October 2007, but it ended up getting pushed back and dumped directly to DVD 2 years later.
 * Case39 was completed in 2007 and didn't get a U.S. theatrical release until 3 years later.
 * Pride And Glory was shelved for 2 years before getting a release date in 2008
 * Paul Schrader shot his prequel to The Exorcist, but studio Morgan Creek had not much faith in it and instead ordered Renny Harlin to shoot his own version, 2005's Exorcist: The Beginning. Eventually Schrader's version was released as Dominion: Prequel to The Exorcist one year later.
 * The John Cusack and Chow Yun-fat film Shanghai was finished in 2008, but was delayed from getting released anywhere until 2010, where it was released in China and other countries, but as of 2012 still has not yet been released in the U.S.
 * RoboCop 3 completed production in 1991, then sat on the shelf for two years while Orion Pictures went bankrupt. The film was eventually released in 1993 to weak box office and scathing reviews.
 * A month before its scheduled release in theatres, Paramount Pictures announced that it would be shelving the completed G.I. Joe: Retaliation until March 2013, supposedly so they could make a 3D conversion as well. It was also rumored that the delay was caused by the weak domestic performance of Battleship (a fellow Hasbro property), and that the director of Retaliation didn't know the film was being delayed in the first place.
 * Warriors Way was completed in 2008 but not released until 2010.

Live Action TV

 * At Last The 1948 Show (1967) was so-called because ITV supposedly kept shows sitting on shelves for months or years before finally deciding to air them. (Not to mention the fact that ITV didn't actually go on air until 1955.)

Music

 * The Beatles recorded the songs which became the album Let It Be in 1969 but then shelved the whole thing and went back to the studio, producing and releasing Abbey Road in 1969. Let It Be (along with its accompanying film) was released in 1970.
 * When Willie Nelson signed with Atlantic Records in 1973 he recorded two albums worth of material at the same sessions. One was his first "outlaw country" album Shotgun Willie, the other was a gospel album called The Troublemaker. Nelson actually thought The Troublemaker turned out the better of the two, but Atlantic didn't think a gospel album would sell so they shelved it. After releasing one more album on Atlantic (Phases & Stages) he moved to Columbia Records, and Atlantic let him have the master tapes for The Troublemaker, which he finally released on Columbia in 1976.

Video Games

 * Blaster Master: Blasting Again for the PS1 completed development in 1999, but wasn't released until 2001.
 * The Red Star, a PS2 shoot-'em-up based on the comic book of the same name, was finished in 2004, but released in 2007.
 * The Dead of The Brain 1 & 2, a TurboGrafx-16 port of two visual novels originally released for the PC-98, was initially scheduled to be released in 1994, but shelved due to the dwindling support for the PC Engine in Japan. Dead of the Brain was eventually released in 1999 in limited quantities, more than two years after the previous PC Engine release (Hataraku Shojo), giving it the distinction of being the final official game for the system (as well as a year after the final PC-FX game, which meant that the PC-Engine technically outlived its predecessor).