Mercury (Score 1)

Don't change them all back yet. Here is the deal, Lights use electricity, a lot of electricity comes from burning coal, burning coal releases mercury into the air. So by using less energy, less mercury is released into the air than is in the compact fluorescent bulb by a factor of maybe around 5. Plus there is less Cadmium, sulfur, carbon dioxide etc being released or produced. So it is a win win game, you save more money on energy than the pricey little bulb costs, you save falling of the ladder to get to all the burned out regular bulbs, there is less pollution, and you prevent global warming. Now, if someone would come up with a good way to recycle the bulbs and mercury, we could close the loop. I believe Australia is going to ban incandescent bulbs - which has a drawback since it will take longer for those bright ideas to pop into your head if you have a ballast.