Most Fashionable Couples

See Tom & Katie, Nick & Jessica, and 10 other stylish celeb duos, as selected by PEOPLE style expert Danielle Dubin. By Serena Kappes

JESSICA SIMPSON & NICK LACHEY

Whether dressed down (left, in New York City) or decked out (right, in Beverly Hills), Simpson and Lachey's style is all about being "young and fun," says PEOPLE StyleWatch writer Danielle Dubin. "They don't disappoint when they go out to red-carpet events where they know all eyes are on them."