Here we go...

1. Terminator (series T-n with n<1000)
2. Astro-Boy
3. Vision (Marvel Comics)
4. Gort
5. Mega-Man
6. ..
7. Awesome-O as seen in South Park
8. Housekeeper (Rosie) from The Jetsons
9. Robot from The Day the Earth Stood Still
10. ..
11. Robby the Robot (The Forbidden Planet)
12. Sentinel from X-Men media
13. Marvin from HGTTG
14. Wheatley from Portal 2
15. Woody Allen in Sleeper
16. Robot from Metropolis
17. Optimus Prime
18. Wall-E
19. Robot from Power Rangers
20. Voltron
21. EVE (from Wall-E)
22. C3PO (from Star Wars)
23. Bender (from Futurama)
24. Brainiac (Kryptonian robot from Superman comics and animated series)
25. Clank (from Ratchet and Clank)
26. Cyberman (from Doctor Who)
27. Cylon (from Battlestar Galactica)

Thanks @CandiedMango, @JasonBaker, @WadCheber for assistance!