HPS lamps are good for plants that are budding, and MH are good for plants that are vegging. These lights come in many different wattage, but I'm using a 400w HPS light. The bulbs themselves are easy to get, I was able to steal mine from Home Depot. The ballasts, however, will cost you a lot more, and unless you like doing buisness over the internet, may be hard to find. I was able to find a few hydroponic supply stores in my city.
Of course, either light by it self, or even a combination of the 2 will produce a good crop, but a general rule of thumb is that young, vegging plants prefer light in the blue part of the spectrum, somthing like ~450 on those charts up there ^. A budding plants prefers red light, ~675. I agree with Thujone that CFLs are the way to go with a small crop. My plants were growing under CFLs for the first 2 weeks, but I switched em to HPS when they got a little bigger. You definately CAN use CFLs to grow a great crop, but I used the HPS cause I had it available.
You have to wait until the plant flowers before you know the sex, I dunno who told you to look at the sprout, but their wrong.