Clint Eastwood's Mystic River got a major Oscar boost Wednesday when the The National Board of Review named the acclaimed drama the best film of 2003. Sean Penn was chosen best actor for his roles in Mystic and the just-released 21 Grams, while Diane Keaton won best actress for Something's Gotta Give. Supporting kudos went to Alec Baldwin for The Cooler and Patricia Clarkson for Pieces of April and The Station Agent. Edward Zwick was named best director for The Last Samurai.