An elegant British brand, that sells very well across the world. It got its unbelievable popularity after Kate Middleton wore Reiss's white dress Nannette during the engagement photo shoot. After selling out of the first run, the brand released another one right away. A cocktail dress like that will cost you about $300 in Reiss. For the complete experience, go to the store in Chelsea, across from Jigsaw. That's the one Prince William's wife visits most often.