Renée Zellweger and Ewan McGregor leap into Rock Hudson and Doris Day territory with a candy-bright, innuendo-filled battle of the sexes when her small-town girl meets his man-about-town. Sparks fly in Down With Love as she champions her anti-love proto-feminist theory and he tries to debunk it. It all makes for a spectacular, if winking, period simulation, with lots of split screens, fab costumes, and ridiculous plot twists. But ultimately, revisiting a genre should involve more than a gee-whiz-we're-really-doing-this attitude. Love, like the supposed preliberated woman, looks pretty but doesn't have much to say. EXTRAS Director Peyton Reed (''Bring It On'') is mostly concerned with giving props to the props in his commentary, but a music video gives the ''Chicago'' and ''Moulin Rouge'' stars another chance to sing and dance.