Fluorescent or hid Comaparison
Until the early 1980's most indoor growers used fluorescent lights to illuminate their garden. These tubes have tremendous advantages over incandescents. They emit about 3 times as much light as an incandescent (given the same wattage), and the light spectrum is one that plants con use more effectively.
However, they do certainly have their limitations. Light is emitted over a large area, so it is not concentrated. Because of this, the lights have to be hung very close to the plants (usually within 2" or so from the grow tips), and constantly moved to accommodate plant growth. This makes garden maintenance rather difficult, even when the lamps are hung on chains.
Florescents are, however, very useful in cloning, and starting seedlings. Because in these stages, a plant is not growing vertically very quickly, the disadvantages of moving the lights are reduced. They also put out a more gentle light than the HID lamps, and release less heat. The fact that they produce less heat is very important to those growing in enclosed and not-especially-well ventilated spaces.
If you choose to use fluorescents, it is best to purchase the 'cool white' variety. The ones that are sold as grow lamps (including grow-lux, vitalite, etc.) are much less efficient than a standard fluorescent, and just do not put out enough light to be useful. The slightly different spectrum produced by these lamps does nothing for most plants. Some growers have reported excellent results by using a mixture of cool-white and warm-white lamps in a florescent fixture.