The White Ribbon reminds us of the enormous power of black and white films. This film is visually wonderful, with its painterly compositions, interesting faces, and occasional frames in which the subject is partially obscured. B&W adds a subtle layer of artifice and historic distance to our experience as viewers.
The story and characters are interesting, too, and the ending is open-ended in a pleasing way that helps keep its rich thematic potentials from lapsing into didacticism or a single, oversimplified observation.
The story is enough to keep our interest, but I also liked its thematic seriousness, something for everyone. Like all good art, it does more than one thing at once. The White Ribbon can be seen (and doubtless will be in graduate student papers) as being primarily about early 20th-century history, the German character, gender conflict, inter-generational conflict, the Holocaust to come, sociology (e.g. society repression, authoritarianism), provincialism, or psychology (particularly aberrant inflections), children, or class warfare. In fact, it is about all of these.
I was also happy that there is no musical sound track. All the music arises naturally from the story as festival dance music, or church hymns. We do not need soundtrack musicians in this film to manipulate our responses. The story and the visuals do that quite nicely by themselves.