Christmas - By far I put up more lights up for Christmas than Halloween. In 2009 I started switching to LED lights. Two reasons, first the electric bill which grew each year and power. LED's reduced my electric bill about $100 in 2009. LED's require less amps so I'm able to add to the display without the need to have the local electric company add another line to the house.
LED's are getting cheaper, they should last longer than conventional lights and while the different shade of "white" or "clear" bulbs takes some getting use to the colored bulbs I think are much brighter. As with older bulbs it is important to try and purchase the same brand and tint of LED. All the clears or whites are not the same.
It's best to buy LED's after the holidays. I purchased about 5000 LED's for the 2011 season at local retailers between December 26th and January 2nd from 50 to 75 percent off. Most of these are to rewire the wire objects (about 26 reindeer, sleds, etc) in the yard. It's cheaper to rewire my existing objects than it is to try and replace them. The newer LED wire decorations don't have as may lights and while they are pretty I like more lights. It will take a bit of time to do but worth for 2011 Christmas.
The music and lights are also a neat and fun thing to do. It takes a bit of time just listening to a song, thinking about how you want the lights to dance and them programing them to the lights. Each 3 minute song might take between 40 and 80 hours of programming. I plan to spend more time on this for 2011. I would like to make a taller lighted tree for 2011 with more lights, we'll see. If anyone is interested in this look for Light-O-Rama. They have everything you need from small systems to as big as you need. Their tech support is great, I've had to use this a few time (due to weather issues not anything they did) and they respond at all times of the day, they are not just a 9 to 5 operation. They have a huge sale in late June early July and it's well worth looking them up.