Interesting. I certainly prefer the light from incandescent bulbs, but have switched to compact fluorescents for almost every light in my house. They use a fraction of the electricity. Mountaintop removal coal mining, coal-fired power plants, and nuclear power plants aren't very paleo. I prefer to look at the bigger picture: how do my decisions affect not just me, but my family, my community, and the whole world. I know I'm not exactly changing the world by changing a light bulb, but I try to make as small an impact as possible, environment-wise.
The light-spectrum stuff posted above was intriguing, though....
