If you are a movie buff, you definitely know www.imdb.com, yes?
One goes there for movie reviews, dvd release dates, to read up a few tidbits about his favorite star, find movies that he likes and various other things.
There is this guy Nathaniel Johnston, who chose to conduct a research on imdb films, their ranking and stuff. I came across this blog of his, when I was searching for movies having ratings higher than 9.0.
His research and formulas not withstanding, he provided a list of movies from 1950 till date that has the highest ranking given that they had 1000+ votes. In the 59 years of the available data, there was one movie that stood out for me.
Jaane bhi do Yaaron. I've not seen the movie in its entirety, but do know it was a superb movie. Now, I have to go and watch it completely. Quite an achievement for a Hindi Movie. One can also check out the other movies. Seem very good as well.