6. Sarah Polley
The 33-year-old Canadian actress turned director with grit and grace in 2007's Away From Her, starring an Oscar-nominated Julie Christie as a wife displaying the first sign of Alzheimer's disease. Polley's filmmaking proved as deeply affecting as her acting in such films as The Sweet Hereafter and Exotica. Last year, with Take This Waltz, she sharply delineated the disintegration of a marriage between Michelle Williams and Seth Rogen. And now there's Stories We Tell, a remarkable documentary in which Polley uses her own life as her subject, notably the fact that she was the product of an adulterous affair.