By Kat Giantis
Special to MSN Entertainment

That Was Jen, This Is Now: When it comes to major life decisions, few are more critical than selecting the gown that you'll wear to walk onstage at the Academy Awards and stand in front of your ex-husband and the woman he ditched you for -- not to mention the millions of tabloid-devouring viewers eager to tear you apart. In magnitude, it ranks right up there with picking the person you'd want to pull the plug should the time ever come. This was a defining moment for Jennifer Aniston, who, to her credit and our surprise, didn't blink. While the preternaturally toned and incandescent star's taste in beaus may be questionable (although her self-described "Oscar boyfriend" John Mayer did wear the heck out his tux), her sense of style is impeccable. She boldly breaks free of her basic black comfort zone and slips into a beaded strapless Valentino number seemingly tailor-made to blind Brad Pitt and Angelina Jolie with its sparkly awesomeness. Simple yet sublime, understated yet assured, it's the perfect couture complement for an actress who just scored two No. 1 movies in a row and stared down the big 4-0 with aplomb. And despite seeming a mite nervous while presenting with the epically laid-back Jack Black, Aniston likely drew strength from her own version of armor -- her trademark gleaming, unfussy tresses, which she dresses up with an abbreviated French braid across her forehead, a neo-bohemian look that we're guessing will soon appear on many a former devotee of "The Rachel."

(Retna Ltd.)