* Critics: Rotten Tomatoes Top 100 Movies of All Time

Movies with 20 or more critic reviews were considered in making the Best of Rotten Tomatoes list, and every movie that made this list got a 100% score on the Tomatometer!  Here is the list from June 2012 filtered for just movies with release date through 1960 (with the number of positive reviews noted):

1. The Wizard of Oz (75)
2. Rear Window (62)
3. Citizen Kane (61)
4. North by Northwest (61)
5. The Third Man (59)
6. All About Eve (56)
7. Laura (56)
8. Seven Samurai (53)
9. Modern Times (52)
10. The 400 Blows (51)

That was the TOP TEN in their list (as filtered for movies released through 1960).  Here is the remainder of their list:

11. King Kong (50)
12. On the Waterfront (50)
13. Rashomon (47)
14. Singin’ in the Rain (45)
15. The Adventures of Robin Hood (44)
16. The Philadelphia Story (44)
17. The Maltese Falcon (43)
18. Rebecca (42)
19. 12 Angry Men (41)
20. Battleship Potemkin (41)
21. City Lights (41)
22. The Treasure of the Sierra Madre (41)
23. Anatomy of a Murder (40)
24. Frankenstein (40)
25. M (40)
26. The Bride of Frankenstein (40)
27. Pinocchio (39)
28. The Grapes of Wrath (39)
29. The Wages of Fear (38)
30. The Cabinet of Dr. Caligari (37)
31. The Rules of the Game (37)
32. The African Queen (37)
33. Tokyo Story (37)
34. Top Hat (37)
35. Kind Hearts and Coronets 36)
36. Stagecoach (36)
37. Rio Bravo (35)
38. The Gold Rush (33)
39. The Birth of a Nation (32)
40. Quay of the Goldsmiths (31)
41. The Invisible Man – 1933 (31)
42. The Killers (31)

See their full list here: Rotten Tomatoes Top 100 Movies of All Time