A new coat is often the centerpiece of fall wardrobes, the must-have item that elevates and refreshes everything beneath it. For next fall the shiny coat will confer an up-to-the-minute aura on its wearer. Many of these are trench-styled, giving the coats a film noir heroine mystique. Jet black is always right, but these are also shown in lipstick reds, inky blues or greens, creamy camels and browns. True patent leather is for luxe versions, but pleather, vinyl, nylon or even plastic-coated poplins work too.