CFL bulbs

I rather like CFL bulbs. They don't get insanely hot, their light is great (the slightly more expensive daytime ones: they're very white compared to the rather yellow incandescents and the slightly sallow regular ones), and they don't waste 80% of their energy from heat.

They look kinda cool, too.

LED lights are the next Cool Thing: you can emulate natural light better with different color LEDs.

I should finish my macro ring-light sometime. not sure how well it'll work though, or how quickly it'll eat through 9V batteries, or if it'll just short and toast all my LEDs.