What type of corals do you want? For reef tanks you have four choices. You can go with T-5 florecent, VHO
florecent and PC
florecent. In addition you could elect to go with MH
lighting or any combination of the four types.
If the tank has a center brace you will need two MH
bulbs mounted so they are the same distance left and right of the center brace so as to cancel the shadow effect.
The acutal lighting setup is somewhat dependant upon the ultimate goals for what types of coral and inverts you wish to keep.