LED Christmas lights are very efficient: the use a tiny amount of power (80% less than regular ones) and last ten years or more. The vibrant colors put out by these lights are not available with traditional Christmas lights. The reason for that is the color isn't achieved by placing a colored glass over a clear bulb, the color being emitted is actually part of the light spectrum. Available for $9.95-$18.95 from Gardener's Supply Company or Amber Leaves. See also these LED lights from Brookstone we featured previously.