Shoulder-length hair is great for round faces. Subtle waves that don't add volume at the sides work great for round faces. Notice the bangs that sweep at an angle across Akerman's forehead. This breaks up the rounded curve of her hairline and give the face angles it didn't have before.

OK, sure. Alba's worst day is our best. But this cut is nonetheless a perfect example of a bad choice for women with square faces. While a medium-length hairstyle is great, bangs rarely, if ever, flatter a square face. Bangs are great for round faces because they create angles. So it follows that they're not so great for square faces, because they create more angles on an already angular face.

A "long bob" is one of the best options for the square-faced woman. The angled bottom and face-hugging sides soften the jawline. A center part further de-emphasizes angles and facial width.

It helps to be drop-dead gorgeous and quite nearly perfect if you're going to break every rule of hairstyling for your face shape. We're talking about Washington in this photo, of course. The rest of us with heart-shaped faces need to remember that it's best to avoid medium-length hairstyles that emphasize the forehead and have lots of volume at the sides.

Witherspoon knows how to make the most of her heart-shaped face, no matter what her hair length. This medium-length style hits all the high notes: soft, long, angled bangs across the forehead, length that hits past the chin, and sleek no-volume sides. The angled bottom adds even more softening and sophistication to this cut.