Most decorators agree that a simple change of paint color in a room is the fastest and most dramatic way to freshen up your space. But what color to choose? If you paint the walls the wrong color, it can be a costly mistake. Make use of technology and paint your rooms virtually online before you make a commitment. Websites like bhg.com and benjaminmoore.com offer free virtual painting, so upload your photos and see what different colors look like in your home. Daffodil yellow, anyone?