The Robot: An automaton initially conceived to be a robotic replacement for a dead woman named Hel, but who is instead used as an evil Doppelganger for union activist Maria (Brigitte Helm).
The Human: Mad scientist Rotwang (Rudolf Klein-Rogge), who built the robot in honour of Hel but who quickly abandons robo-romance in favour of political unrest.
The Friendship: It's lucky the robot has been programmed to obey Rotwang, given the latter's lack of fidelity in pulling a last-minute switcheroo in 'her' appearance.
I, Robot (2004)
The Robot: A rogue NS-5 robot known as Sonny, who can break the Three Laws of Robotics and may be a murderer.
The Human: Prejudiced cop Del Spooner (Will Smith), who mistrusts and fears robots and goes on the hunt for Sonny.
The Friendship: Sonny is the killer, but he's a pawn in a greater conspiracy, and becomes Spooner's invaluable ally as the cop learns to trust a robot.
Short Circuit (1986)
The Robot: Number 5 (voiced by Tim Blaney), a damaged Cold War warrior with a new lease of life after being struck by lightning.
The Human: Hippyish Stephanie Speck (Ally Sheedy), whose instincts as an animal carer cause her to look after the malfunctioning robot.
The Friendship: Speck gives Number 5 the input it asks for, effectively reprogramming the robot's military function with more touchy-feely sentiments.
Forbidden Planet (1956)
The Robot: Robby The Robot (voiced by Marvin Miller), a space age Ariel who serves as a butler on planet Altair IV.
The Human: Dr Edward Morbius (Walter Pidgeon), sole survivor of an expedition who built Robby after having his intellect expanded by alien Krell technology.
The Friendship: Loyal Robby won't harm his master, which isn't very helpful considering the planet is under threat from a monster created from Morbius' id.
A.I. Artificial Intelligence (2001)
The Robot: Child droid David (Haley Joel Osment), created as the perfect child with unconditional love.
The Human: David's "mother" Monica (Frances O'Connor) who activates the imprinting protocol that causes her robot son to focus his affections on her.
The Friendship: The honeymoon period doesn't last long; when Monica's human son is cured of his life-threatening disease, David becomes superfluous to requirements… but note that Monica can't bring herself to have David destroyed and instead abandons him with at least a chance of survival.
The Robot: Bishop (Lance Henriksen), the android assigned to the Sulaco mission to alien stronghold LV-426.
The Human: Ellen Ripley (Sigourney Weaver), traumatised survivor of a previous xenomorph encounter… and paranoid as hell about androids after being attacked by one aboard the Nostromo in Alien .
The Friendship: That initial fear turns to grudging respect and finally acceptance, as Bishop proves his mettle by undergoing a dangerous mission to pilot a rescue dropship.
Star Wars (1977)
The Robot: R2-D2 (Kenny Baker), doggedly determined dustbin-shaped astromech droid.
The Human: Luke Skywalker (Mark Hamill), technically his owner after the death of Uncle Owen at the hands of Imperial Stormtroopers.
The Friendship: Rocky at first because Artoo is on a mission for Princess Leia. Yet after providing technical support during the attack on the Death Star, accompanying Luke to Dagobah and smuggling a lightsaber onto Jabba's sail barge, he's indispensable.
Terminator 2: Judgement Day (1991)
The Robot: T-800 (Arnold Schwarzenegger), the one-time Skynet assassin reprogrammed by John Connor in the future to protect his younger self in the Nineties.
The Human: John Connor (Edward Furlong), obviously.
The Friendship: Arnie becomes the father figure that John never had. In return, the future revolutionary teaches his cyborg pal how to cry and answer back in Spanish.
The Iron Giant (1999)
The Robot: The titular alien (voiced by Vin Diesel), who crashes in 1957 America with his memory banks damaged.
The Human: Nine-year-old comic-obsessed Hogarth Hughes (Eli Marienthal), who finds the Iron Giant and realises he has his very own superhero.
The Friendship: Hogarth teaches the Iron Giant about heroism; the robot duly responds by protecting the boy (albeit often misguidedly) from threats real and imagined.
Silent Running (1972)
The Robots: Three drones - known as Huey, Dewey and Louie - aboard the Valley Forge, tending to plant life preserved after Earth could no longer support it.
The Human: Botanist Freeman Lowell (Bruce Dern), who needs the drones' help after he kills his crewmates to stop them jettisoning the flora.
The Friendship: Absolute. Freeman teaches the drones to play poker - badly - while they remain loyal to the last, risking damage, destruction and eternal loneliness. You'll cry.