I was on a big Bergman kick about 5 years ago, but there are still a couple that really stand out for me (in chronological order):

1. The Devil's Eye
2. The Rite
3. Cries and Whispers
4. Scenes from a Marriage
5. Autumn Sonata
6. From the Life of the Marionettes

And here's a few weak ones:

1. The Touch -- This one comes from my favorite Bergman era, but it just doesn't work.

2. Fanny and Alexander -- Sorry, there are hundreds of directors out there who've made movies like this one.
 
3. Monika -- Zzzzzzzzzzzzzzzzzz