Terminator Salvation (2009)
The Robot: Marcus Wright (Sam Worthington), a cyborg who has been programmed to believe he is human, in order to infiltrate the confidence of Skynet's greatest threat.
The Human: John Connor (Christian Bale), the saviour of mankind who remains Skynet's number one target in order to prevent him succeeding in his rebellion against the robots.
The Friendship: A fragile truce is forged after Connor realises Marcus' true nature. His gamble in trusting the cyborg pays off when Marcus volunteers his own heart to save Connor's life.
The Robot: GERTY, the emoticon-wearing computer aboard the Sarang lunar mining base, who controls things via a system of robots tethered to an overhead rail.
The Human: Sam Bell (Sam Rockwell), the only member of the base crew. Well, technically. Actually, there are loads of Sam Bell clones in storage waiting for their turn to serve, and one of them has just been defrosted.
The Friendship: GERTY is a company stooge, programmed to keep Bell's clones a secret, but he breaks protocol to help the two Sams cover their tracks.
The Robot: Autobot warrior who can disguise himself as a Chevrolet Camaro but is so battle-damaged he can only speak through the strategic playback of songs on the radio.
The Human: Sam Witwicky (Shia LaBeouf), a high school student who becomes a target for the Decepticons after they discover his possession of the all-important All Spark.
The Friendship: Bumblebee is a faithful - if sometimes overzealous - protector of Sam, although by third film Dark Of The Moon , he's relaxed enough to head off on Autobot missions without his human pal.
The Robot: WALL-E, a Waste Allocation Load Lifter who escapes Earth with fellow robot EVE to visit the remnants of humanity aboard the spaceship Axiom.
The Human: Captain B. McCrea (Jeff Garlin), supposedly in charge of the Axiom but really leaving things to the ship's computer while he slobs around like the rest of the humans.
The Friendship: Admittedly, the main relationship here is between WALL-E and Eve; nonetheless, the film's big Epiphany is McCrea's realisation - sparked by his interest in the robot visitor - that there must be more to life than this.
Star Trek: First Contact (1996)
The Robot: Lieutenant Commander Data (Brent Spiner), struggling both with his new emotion chip and with the fact he's been captured by the Borg.
The Human: Captain John-Luc Picard (Patrick Stewart), facing up to his nightmares of assimilation as he seeks to prevent an attempt by the Borg to change the future.
The Friendship: Data's allegiance to Starfleet is tested by the Borg Queen, who helps him to become more human by giving him skin grafts... but if anything, that makes him more loyal to his captain.
The Empire Strikes Back (1980)
The Robot: Protocol droid C3PO (Anthony Daniels), versed in over six million forms of communication, but who struggles to socialise in any of them.
The Human: Han Solo (Harrison Ford), en route from becoming roguish, amoral smuggler to a hero of the Rebellion.
The Friendship: Friendship, really? Surely Han hates Threepio? But we think the smuggler doth protest too much. Having a droid stooge is perfect for bigging himself up with Leia, and if he really couldn't stand the goldenrod he wouldn't have let Chewie repair him.
Blade Runner (1982)
The Robot: Rachael (Sean Young), a replicant who thinks she is human thanks to falsely implanted memories.
The Human: Rick Deckard (Harrison Ford), a replicant-hunting blade runner who is ordered to kill Rachael by his superiors. [Yes, he's human: the film's theme of jaded Deckard rediscovering his humanity doesn't make sense if he's a replicant.]
The Friendship: Deckard has fallen in love with Rachael and decides to start a new life with her, even though he knows she only has a few years to live.
The Wizard Of Oz (1939)
The Robot: Well, we say robot. He's more of a tin man. But this literally heartless automaton (Jack Haley) is arguably Hollywood's most influential prototype for future screen robots.
The Human: Dorothy Gale (Judy Garland), whose journey down the Yellow Brick Road to get back home is as good an excuse as any for the Tin Man to seek an audience with the Wonderful Wizard of Oz.
The Friendship: The tinsmith might have forgotten to give him a heart, but the Tin Man hardly needs one when he's supplying the brains and bravery that are in short supply amongst his travelling companions, the Scarecrow and the Cowardly Lion.
The Day The Earth Stood Still (1951)
The Robot: Gort, a giant metal visitor to Earth with the power to destroy life… unless somebody yells "Klaatu barada nikto" to get him to stop.
The Human: Gort's owner, Klaatu, a Christ-like extraterrestrial who has arrived on Earth to convince world leaders to stop using atomic power before they destroy everything.
The Friendship: Gort is programmed to go loco should anything happen to Klaatu… which seems counter-productive given that their ship has the power to bring the latter back from the dead.
The Robot: Robocop (Peter Weller), the prototype cyborg officer created from the ravaged body of human cop Murphy.
The Human: Officer Lewis (Nancy Allen), Murphy's partner before his accident.
The Friendship: Once Lewis clocks who Robocop really is, it's business as usual for the crime-fighting duo.