There are some purists who like their robots to be totally devoid of emotion. Then there are those, like me, who like the full range of robot "emotion" in their music (call me sentimental). So, let's imagine some sort of robotic "emotion chip" and consider some musical examples...

MELANCHOLY
Let's face it: robots go through existential crises too, whether it be from loneliness, heartbreak, or doubts about their purpose in the world. And humans can sympathize with robots: when the robot sings in Kraftwerk's Radioland, I get a lump in my throat...

= mr_hopkinson's computer™ does a haunting cover of The Smiths song Asleep on the album Mr_Hopkinson's Computer Sings, available here.
= Solvent does a lovely, bittersweet version of Slowdive's When The Sun Hits from Blue Skied An' Clear: A Morr Music Compilation.
= Memory Boy as a broken-hearted "emo" robot in There Is No Electricity from Ghostly International presents Tangent 2002: Disco Nouveau.
= Wolfgang the robot has a touching back story behind Not In Love Not True.
= Microvax - Robarthes is a pensive French robot. Je pense donc je suis.

SWEET
Robots are cute: just look at Astroboy, or real life robots ASIMO and PaPeRo, they're adorable.

= Tobiah's epic chiptune I Love Your Music from the Glitter & Bleep (Joystick Pop) compilation, also available at Micromusic.
= ISAN - Iron Eyes, from the album Meet Next Life.
= Plastik Kettle - Green Travel, from the album Our Toys Are Better Than Yours (a great title). Fans of the Suction Records robots will like this.
= Plone - Plock, from the album For Beginner Piano. Shame on WARP for never releasing Plone's still unreleased 2nd LP.
= Mikron64 - Ikea, from the Etwas Zeit EP.

HOSTILE
Obey these sinister robots or they will crush you. Translation: "Destroy All Humans!"

= Industrial Bass Machine - Devastate The Planet from the excellent album, A Taste of Armageddon.
= Datathief - Night Raid from the SKAM compilation Skam 0161.
= Tinfoil Teakettle - Think Like Us, from the Suction Records compilation Snow Robots Volume 3.
= Datassette - Run Human!, from the Maintenance Werk EP available for download here.
= Mr. Velcro Fastener - Real Robots Don't Die from the album Lucky Bastards Living Up North.

ARROGANT
You have to love a robot with an ego: Pushin' more power than a Duracell. These are "funky" robots, here to give you what you need, and what you need is bass!

= Plaid's fantastic remix of Grandmaster Flash & The Furious Five's Scorpio on their remix album Parts In The Post.
= Man Parrish - Boogie Down Bronx. Just a 'bot from the block. On the real.
= Exzact - Sub.Sonic. Base from the Second Wave EP.
= Solenoid - The Narcissist from the album The Narcissist.
= Multiplex - Rock Robot, from the Pinghaus Frequencies LP.

ROBOTIC
Sometimes robots just sing about being robots, okay? Whether it be data, hard disks, calculations, or being made of metal...or "making circuits" with pleasure bots.

= Console - 14 Zero Zero, from Rocket In The Pocket is one of the best robot songs ever.
= Bochum Welt - Feelings On A Screen. Yes, the title of this article is taken from this song.
= Abfahrt Hinwil - Syntax Data, from the Toytronic compilation, Neurokinetic.
= Hong Kong Counterfeit - Metal Disco [Legowelt vs. Orgue Electronique RMX].
= Gimmik does math in Rc Units from Slow Motion Process.