Period films, those of the proper British accent and corset variety, may be the trickiest of genres to pull off with freshness and flair. Without a vibrant visual sense or subjective identity to call their own, they more often than not resemble a dry BBC production of "Masterpiece Theater." Director Mira Nair has proven with her last two features, 2001's enchanting Monsoon Wedding and 2002's woefully overlooked gem, Hysterical Blindness, that she has a keen filmmaking sense and an adeptness for characters, two valuable traits she attempts with varying success to bring to Vanity Fair