Metal Halide is best for the vegetative stage, HPS High pressur Sodium for the flowering stage,the penetrating power of HID is by far the best,The only downside is they produce a fair amount of heat,depending on the temps in your region you may or may not need to cool your reflector hood,that's if you decide to go 400 watt or higher,250 watt and lower are generally pretty easy to keep cool with proper ventilation.I use regular fluorescent for the vegatative room with great results.I purchase the lights and fixtures at Wal-Mart,the fixtures are $9-$10 that hold two lights,and the two packs are $7-$8.You can also use Cfl (compact fluorescent) lights that simply plug into a regular light sockets.I dislike these myself ,just too many wires every where.If you do decide to use fluorescent lighting you need your lights to be 6500k color temp. bulbs for veg,3000k color temp. bulbs for flowering,I use 1 of each in each fixture in my veg room.For flowering as stated above high pressure sodium is the best way to go for the nicest, juciest, compact buds.Some high output fluorescent lights have good results but HID is better hands down,now if you need to be super stealthy fluorescent is the way to go.