Wild Strawberries and Persona are both very excellent, engaging films. Through a Glass Darkly is also one of my favorites. Bergman's use of music, the Bach cellos suites, is especially poignant in that film.
My absolute favorite Bergman film is not one that impressed me most the first time I watched it - The Passion of Anna.
I keep being drawn back to this movie and it's grown on me over time. There are scenes that feature one character in a long duration shot telling a story. This mode of storytelling in film is difficult and requires top-notch writing and acting to be pulled off. Bergman pulls it off beautifully.
The Magic Flute is another one of my favorites. That film features another writer as part of the pair of protagonists, like The Passion of Anna.