11. The Trench Coat — What? You don't have one of these already? C'mon! If somehow the trench has eluded you (or you have one, and it's just all wrong), then it's time to make a critical investment. If you have the extra money to spend, take the time to find a trench that fits like a glove and offers the kind of quality and detail that will last a lifetime. If not, there are plenty of wonderful new trench options out there well under $200 that'll make you feel like the style star that you are…and that's what a great trench is for, period.  

Yves Saint Laurent Cotton Coat, $2,990, available at Net-a-Porter; Costa Blanca Double Breasted Trench, $77.99, available at Shop Ruche.