I got the Criterion DVD and it has a wonderful essay and special features that comment on the ending. The original ending was rejected by the censors (oddly the only part of the movie that created an objection).
****spoiler****
It ended with Viridiana going into her cousin's room, sitting on the bed and closing the door. They were all alone and clearly implied they were going to have sex. According to Silvia Pinal the censors said that a devout virgin would never throw herself at another man that late in her life!
Bunuel thought up the ending apparently on the spot, and Pinal claims grew to like it more. She said it was supposed to represent an impending menge a trois. He told her to play it as if for the first time in her life she would be of some real use. She had given her life to the church and the betterment of humanity, and this was ultimately a waste. Now she would be able to have children, work the land, do some real good in the world. Pinal seems dejected at the end to me, but this was her motivation.
****end spoiler****
I'm still thinking about this like crazy today. I'm sure it will only get better with multiple viewings. This reminded me a lot of Diary of a Chambermaid in style, another awesome Bunuel film.
I feel a little pretentious telling people that I love Bunuel and think he is brilliant, but I really mean it! I think he totally deserves he reputation as one of the greatest directors of all time.
Marie: Don't be in such a hurry about that pretty little chippy in Frisco.
Tony: Eh, she's a no chip!