Kristen Stewart, Breaking DawnWe admit it: in our vampire-loving hearts, Bella Swan's onscreen wedding dress was more exciting than Kate Middleton's — and Pippa's — real-life Royal Wedding ensemble combined. Designed by Carolina Herrera, Bella's gown is a sleek creation of crepe satin, French Chantilly lace and 152 covered buttons with a cut-down-to-there keyhole back (the better to tempt her ot…