2009 Prom Dress Trend One Shoulder Gowns. For 2009 one shoulder gowns and dresses are one of the hottest looks. The best thing about this style of dress is that it works for every body type. It a very alluring style that shows just the right amount of skin in all the right place, yet at the same time its classy and elegant. On the red carpet the one shoulder look has been worn on celebrities and stars alike. You can see all the great versions of the one shoulder gown below.