As you can see in our April StyleWatch issue on stands now, the it-accessory for spring is the single round pendant on a chain. Whether the necklace is vintage inspired, a family heirloom or completely modern, celebrities like Nicole Richie, Tyra Banks, Drew Barrymore, Hilary Duff and Hayden Panettiere are keeping it simple with the single charm. You can get Hilary's "Cute as a Button" (left) pendant from White Trash Charms, $125-$375, here and get the gold and ...