Here are my thoughts...

I would probably go with some PCs to light the tank. The 58 gallon is 21 inches deep, flourescent bulbs are usually pretty good to this depth, if you get too much deeper than this you almost have to consider MH (MH is able to drive deeper). The other thing to think about is heat, if you end up getting MH, you will probably have to end up buying a chiller. Plain and simple, MH throws off a lot of heat.