To celebrate Elizabeth and James's new handbag line (spoiler alert: it's awesome!), celebrities flocked to the Chateau Marmont for a fun night hosted by Mary-Kate and Ashley Olsen. As is the case with many a party, guests showed up in outfits that fell up and down the style spectrum. Naya Rivera was our formal favorite in a Naeem Khan Pre-Fall 2013 beaded silk dress, accented with sparkly gold pumps and gobstopper Kara Ackerman studs. Willa Holland went for a tougher, downtown vibe with a leather motorcycle jacket and black shorts, feminized by minty pointed-toe heels. Ashley Madekwe was the most laid-back looker of all, pairing a floral t-shirt with boyfriend jeans, sandals, and a bright blue clutch. What kind of look do you prefer for a Summer shindig? Ultracasual or more polished?