We all know The Godfather and Back to the Future are sacred, but what modern classics should be protected from quick-buck-hunting Hollywood studios?
"Remake" is something of a dirty word nowadays. It is true that most are cynical, but many over the years have proven their worth, becoming classics in their own right.
Scarface, John Carpenter's The Thing and Ocean's Eleven were all remakes that stood the test of time and this week RoboCop hits cinemas aiming to join them. First, however, it has to overcome a very sceptical fanbase.
Film fans get protective of the films they love – as well they should – so the announcement of a RoboCop remake was met with the same trepidation that met the recent Total Recall and Carrie re-imaginations.
There are certain filmsdeemed untouchable but many end up being touched, and touched inappropriately. Back to the Future and Ghostbusters have stood their ground, but what modern classics should Hollywood leave alone when attention turns to them decades down the line?
Here are seven 21st century classics that don't need remakes.
Following The Dark Knight, director Christopher Nolan was essentially given free reign to make any film he liked. Some directors take similar chances to make something on a smaller scale, but Nolan only dreams big.
Pitched as an existential heist movie, set within the layered dreams of a powerful corporate figure, it's not exactly an easy pitch – but the studio had faith in Nolan, and it was a faith that paid off.
Every film on this list is here because it is perfect in some way. Either it's in the performances, the direction or because that film represented a perfect moment in time.
Inception was a perfect combination of ideas, vision and a top drawer cast. It was impactful because it was different, and that would be lost in a remake.
Eternal Sunshine of the Spotless Mind
There is only one Charlie Kaufman, so any attempt to replicate his mastery of the weird and powerful would be foolhardy by anybody's standards.
Why Eternal Sunshine is here over Adaptation of Synecdoche, New York, is mostly down to Jim Carrey. His supporting cast – Kate Winslet, Elijah Wood, Kirsten Dunst, Tom Wilkinson - were excellent, but Carrey gave one of his most surprising, and touching, performances to date.
In Michel Gondry's comic drama he juggles the morose with the slapstick so fantastically that it is hard to imagine anyone else in the role of lovelorn Joel.
Shaun of the Dead
Shaun of the Dead had as big an impact as it did because it took an idea that you'd have thought would have been done already, and ran with it all the way to box office gold.
Edgar Wright's rom-com-zom launched his, Simon Pegg and Nick Frost's careers. It was a confident, stylish comedy that didn't make a comedy tinged with horror, but a comedy horror that gave each genre the love it deserves.
It was the perfect spoof, so in trying it again it would lose its appeal. Maybe, if the action were transported to America, it might find new life – but it already did, in Zombieland.
How would you even start remaking Donnie Darko? Dark, mind-bending, utterly unique - where would a filmmaker event start? It's hard to imagine even director Richard Kelly could make the film again.
His debut feature, Darko was so brilliantly weird even Kelly couldn't replicate its strangeness in his follow-up, Southland Tales, which bombed in 2006 and The Box, which underwhelmed in 2009.
It appears Kelly is a one hit wonder, but what a hit Donnie Darko is.
Often the films that fans want left alone are held in such high regard because they are a perfect representation of their director's vision. When it comes to visionary directors, there are few more deserving of the title than Guillermo Del Toro.
Del Toro's dark, twisted designs are lifted straight out of nightmares we never knew we could have, and Pan's Labyrinth pulls his warped ideas together better than any of his other films.
Simply put there's no other director who could even touch this wonderful grim (and Grimm-like) fairy tale.
Lost In Translation
Sofia Coppola's follow-up to the acclaimed but morbid Virgin Suicides is a wonderful ode to friendship in its purest, most fleeting form. It stars Scarlett Johansson at the start of her career, and Bill Murray, who was a notoriously picky comedy actor better known for bringing us to tears of laughter than tears of sadness.
Lost in Translation's climatic scene, in which Murray's world-weary actor whispers in the ear of Johansson's neglected Charlotte words unknown to the audience will live long in the memory.
It is a moment crucial to the film, and one that could never be faithfully recreated.
Typically a film chronicling an awful historical event would suffer from being made so near to the event itself. Cries of "too soon" levelled at Paul Greengrass' United 93 however were soon shut up when it became apparent that this wasn't a film capitalising on grief, but one showcasing the many moments of heroism that deserve to remembered over the appalling crimes of a few.