Oh, if you're limited in space and you're willing to spend some money on a light, go HPS. A nice 150w or 200w unit would do nice for two plants -- throw in a couple daylight spectrum CFLs during vegetative and replace them with a couple 42w warm white CFLs during flowering. With the CFLs working in unison with the HPS, you can't go wrong.

Always remember -- the fewer lights to have to fuck with the better when dealing with small grow spaces.