Our Christmas tree and most of our other ornamental lights are LEDs. I’m interested to see the electric bill. The outside C9 bulbs were pulling 300watts. The LEDs are probably 3watts at most, they’re not as bright but still look good as they don’t lose their color, don’t scratch, and are shock and break resistant.
You might find this article on LED’s interesting.
http://news.bbc.co.uk/2/hi/uk_news/scotland/glasgow_and_west/7162606.stm