Two bits of news today for high-def enthusiasts: Sex and the City's Cynthia Nixon has signed on to star in HDNet Films' One Last Thing..., about a mother coping with her son's terminal illness. HDNet is the outfit behind Enron: The Smartest Guys in the Room; their mission is to produce high-def features and documentaries for theatrical release. We wish Ms. Nixon luck, because, apparently, for some stars, HD isn't the most flattering medium. ONHD.tv (via boing boing and cinema minima) has a side-by side comparison chart of Stars Who Look Better in HD, and Stars Who Look Worse. Scarlett Johansen "has the skin of a porcelain doll and looks incredible when seen in high-def; Renee Zellweger, meanwhile, is "cute, but her cheeks look like she's had a Roseacea problem; very visible in high-def."