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
VHO=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.
IMHO T5HO is the best way to go, the suggestions I gave above are what you'll want to look at