Metal Halides are hot and expensive, also energy suckers, but very powerful. It seems like they are on a downturn in the aquarium community to me. My LFS
was saying everyones trying to sell their halides and switching to T5s
=Very high output if I'm not mistaken, not sure what the difference is between those and T5HOs, I think melosu has VHOs
With individual reflectors a good T5HO fixture with the right amount of bulbs are much more efficient and no where near as hot as halides.
T5HO is the best way to go, the suggestions I gave above are what you'll want to look at