These are my picks.  Feel free to add yours!

27.Commodus in Gladiator

26. Jason

25. Graboids, Tremors

24. Chucky

23. Government, V for Vendetta

22. Zed's Dead Baby, Zeds Dead

21. Stuntman Mike, Deathproof

20. Miranda Hillard, Miss Doubtfire

19. Lo-Pan, A big problem in little china

18. Buffalo Bill, Silence of the Lambs

17. Lord Voldemort

16. The Flying Monkeys, Wizard of Oz

15. Zed, Pulp Fiction

14. Scar, Lion King 1994

13. Brick Top, Snatch

12. puppets from the puppet master movies

11. Annie Wilkes, Misery - 1990

10.  Freddy Krueger, A Nightmare on Elm Street - 1984

9. Die Hard - Hans Gruber

8. Se7en - John Doe

7. Michael Myers, Halloween - 1978

6. Psycho etc. - Norman Bates

5. 2001: A Space Odyssey - HAL 9000

4. Joker, The Dark Knight - 2008

3. Hannibal Lecter, Silence of the Lambs - 1991

2. Darth Vader, Star Wars series - 1977-2005

1. JigSaw, Saw

*There are many more amazing villians but these are the ones that scared the shit out of me at times haha or were just awesome.  Hate all you want but i like them! lets see how many we can get!