Pick a theme (if you want), but stick to thematic items that are replaceable, like easily removable wall decals, lamps and toys. Big-ticket items like the furniture should be neutral so they can work with different bedding and art down the line. When you're choosing the furniture, consider styles that can grow with baby. If you're investing in a dresser that you'll use as a changing table, be sure it will look okay once your babe is out of diapers and you no longer need that changing pad. If you're going with a convertible crib, make sure you love the way it will look as a bed later on (otherwise, you may want to skip the conversion kit and buy a twin bed instead).