lights!?

idk what people mean by hps and other little names for these different lights. i have a 42'' dual flourescent lamp and 2 cfl's. i went up to homedepot and seen a 420wat sodium light and was thinking about getting it. but i dont kno wich is better, sodium or that metal halide shit. and which lights are the best? could someone reply with a list from like 5-1 with one being the best light bulb. thx

Hps=high Pressure Sodium, Cfl= Compact Flourescent,mh= Metal Halide.
I Think Hps Is The Best For Lighting And Yield. Then Mh. Cfl's Are Great For People On A Budget. They All Work Good And Make Chronic

MH is for Vegatative growth and HPS is for flowering.

but if you can only afford one,,, get the sodium,, "high pressure sodium", this way you can veg with you cfls and flower with your hps,, or veg and flower with your hps, and just add your cfls in the mix,, more light the better...