Nostalgia is a common theme come Christmastime, but there’s no need to resign yourself to fond memories of celebrations long past. With an array of vintage decorations for sale at shops across the North Fork, it’s easy to create an old-fashioned Christmas. From a giant 1950s-themed Santa Claus cutout in Riverhead to a leg lamp from “A Christmas Story” in Southold, we tracked down the very best in retro holiday finds.