Types: CFL's come in mainly two flavors, Soft White (color temperature 2700k) and Daylight (color temperature 6500k). For a complete grow, you should use both. Soft white mimics the spectrum of a HPS light, and is best suited for flowering. Daylight's color spectrum is like that of metal halide lights, and is excellent for the vegetative stage. (This applies to tubes too. Around 6500k for veg, around 2700k for flower.) There are also tubes labeled plant and aquarium. I haven't seen them in CFL form, but they have no real color temp, so I'm not sure on their efficiency, but I've used them and it's rather slow growth for the watts.
-There is a large difference in vegetative growth when going from soft white to daylight. Therefore I recommend you use daylight CFL's for vegging, even if you are flowering with a HPS light, because they do not stretch the plants. You don't need much light for good veg growth, especially when using 6500k CFL's.