Prof. Reynolds has been discussing compact fluorescent bulbs.
I've been using them for years. I put them everywhere I can. I have them in lamps, in the overhead fixtures that pepper my kitchen, living room, and hallway ceilings. Apparently I'm not that picky about the quality of my light. I buy them on sale, in the cheapest per-fixture package I can find. I'm not that green-minded, I just want to pay less for electricity.
My experience has been that they don't seem to last as long as their claims. I'm not anal enough to have actually tracked the time of individual bulbs, but I know I've changed them more often than expected.
I think LED lights will be a better option as that technology matures. I just bought a package of three LED night lights to put in my garage so that - hopefully - my family will quit leaving on the six large overhead fluorescent fixtures for which there is one switch by the door into the house. Not sure why the builder wouldn't have put a switch on the other side of the garage by the door that goes outside. Anyway, the LEDs do a nice job - plenty of light to pick your way around vehicles, lumber, toys, and whatever else might appear in the path between doors.
"Talent is cheaper than table salt. What separates the talented individual from the successful one is a lot of hard work." - Stephen King (1947-)