Alright here's a brief word on lights for ya. Ideally a grower would have 3 seperate lighting setups. For sprouting and raising clones, you'd use compact fluorescent bulbs, but forget the ones that screw in to your regular medium edison-based socket. You want the self-ballasted VHO (very high output) type that screw into the larger, porcelain mogul-based socket. Once your plants grow bigger and a little hardier, and have entered the actual "vegetative" state of growth, you would switch your lamp to a metal halide HID (high intensity discharge). Now I dont know the lumen count per watt off the back of my hand, but halide's are great for vegetative growth because they concentrate most of their light in the blue or "cool" portion of the visible light spectrum. This is ideal because this type of light encourages short internodes and strong vascular (that is, growth of stems and branches) development. Short internodes speak for themselves, and strong branches support big buds. Makes sense enough. Now, once you decide your plants are ready to enter the reproductive phase of growth, (colloquially known as "flowering or "fruiting") you would then switch off your lamp again, this time for a high pressure sodium HID. High pressure sodium lamps are ideal for the reproductive phaase of growth because they focus most of their light in the red or "warm" portion of the spectrum. Light in this area of the spectrum stimulates vigorous and rapid growth, ideal for the developing flowers of a budding marijuana plant. Once again I dont know the exact lumen per watt ratio, but i do know that it is marginally higher than that of a metal halide. All that I have just said would be the circumstances in an "ideal" situation, however, many of us (myself included) simply dont have the money to buy multiple 100$ CFL's, and then multiple ballasts with price tags from 200$ and up. One thing you could do however, is use conversion bulbs. Conversion bulbs are bulbs of one type (ie, MH or HPS) designed to be burned in the opposite ballast. They are slightly more expensive but they are a good solution for those of us who need to pay the bills, feed ourselves, pay for school tuitions, etc. Lol anyways, you might want to read through this a few times to get a good feel for it, hope it helps, and for the love of god, avoid incandescent lights. Simply put they are a waste of time, and if you paid for your seeds, a waste of those too. They produce almost no useable light (for plant growth at least) and a retarded amount of heat.
Happy growin', Sarge