Anything SMG does post-Buffy will seem anticlimactic and it can't be said that she's expanded her acting range in the meantime, or carved deeper channels of implication and filigreed her facial expressions. And yet it doesn't matter. As an actor Gellar is a compelling anomaly. She has a somewhat toneless voice that tips up at the end of sentences and rhetorical questions to denote bittersweet sarcasm, her movements are mostly shoulder-propelled, and her raccoon eye makeup seems like an homage to Lisa Marie Presley--Gellar ought to have all the presence of a sad emoticon on the screen, a flat drip.
And yet she's never less then compelling and sympathetic, and believable in everything her characters do--there's a vulnerable note of pathos in SMG that always rings true, pun perhaps intended. It doesn't hurt that she wears clothes beautifully, her wardrobe as an ice-queen socialite the perfect marriage of money and monastic hauteur.
(Full review is in his blog at Vanity Fair)