What are Different Types of Christmas Lights?

One of the principal differences between Christmas lights of today and those of yore is that LED lights are now offered in a variety of sizes and colors. LED Christmas lights use a semi-conductor to brighten up the tree or the inside or outside of the home. They are extremely energy efficient as compared to the old fashioned mini-lights. In fact, people estimate they save about 90% of their Christmas electricity bill by converting to LEDs.
LEDs come in mini lights, round shapes, and large pointed varieties, and they are more expensive in the onset. However, most people recoup their losses in extra expense on LEDs, particularly if they light their tree regularly.
Also, LED Christmas lights do not get hot and thus pose less fire danger than do regular mini-lights. They are slightly less bright, but can be connected to regular light strands as they connect end to end. Some say that the white lights do not mimic the brightness and glow of mini white lights. This can be addressed by buying a soft yellow or cream LED set instead.
Traditional incandescent Christmas lights are also still quite popular and exhibit many varieties. They can now be found arranged in icicle light formations, a quite popular outdoor decorating choice. Some vary this by using blue or green icicles instead of the more expected white.
For a while, the larger pointed bulb lights were not available. They did get hot and proved a fire danger. Now one can find both LED and incandescent bulbs available for the large bulb look outdoors or indoors. The bubble Christmas lights were also a once dangerous choice, though many people loved them. Safe bubble lights are now also available.

Source: http://www.wisegeek.com/what-are-different-types-of-christmas-lights.htm