Solar powered holiday lights are the way to go this year. Yes, the LED solar powered bulbs are slightly more expensive than traditional lights, but you'll save on your electric bill at the end of the month, especially if you plan to keep your lights on every night, and since these are powered by the sun, you won't have to worry about installing them somewhere next to an outlet.
Solar powered LED lights can be found in just about every major retailer now — online as well as brick and mortar shops. The stand of lights (no matter which brand) require a few batteries to place into the solar panel to help with charging. You then place the solar panel in an area that gets the most constant sunlight throughout the day and the lights charge up allowing them to stay lit during the night.
Target has some great deals on LED solar lights. For a string of 50 White lights, it'll cost you $19.95, but if you go to Amazon, they have a string of 100 lights for $34.00. We're noticing a trend of the more you buy, the cheaper they get per 50 light strand.
Don't forget about Proper Holiday Light Etiquette!
Images: Flickr user Andy Peters under license from Creative Commons, Target & Amazon