Strange how powerful some of Rineke Dijkstra's simple, frontal portrait photographs are. Awkward adolescents on the beach or in the park, young soldiers in uniform, bloody matadors after bullfights, mothers after giving birth -- all looking into the camera with a mixture of defiance and shyness, vulnerability and self-consciousness. Maybe it's because they're all so obviously posing, and never entirely succeeding.
For lack of a good site, check examples @ Google Images.
Or go see the exhibition @ Stedelijk Museum Amsterdam.
(Btw, don't miss her video pieces, especially 'Buzzclub/Mystery World', showing hilarious clubbing kids.)