For hydroponic horticulture are Metal Halide (MH) and High-Pressure Sodium (HPS) lights still the staple/better choice for growing indoors or do Compact Fluoresent lights (CFL) offer enough light output/spectrum to give the HID lights a run for their money? Can CFLs provide enough power to support indoor plants alone (specifically concerning a setup where there is very little sunlight available)?
Also: Perhaps this would be better suited as its own question but, where do LED lights fit in to the plant lighting world?