Kw,
Lots of schools of thought. I have three 6' tanks (2 salt and 1 freshwater). Your lighting should be designed around what you plan on stocking. I would sue different lighting for a predominantly SPS tank than I would for an LPS/Softie/Zoa tank since cost can be such an issue.
Then there is alos the prefernce of T5 vs MH vs VHO....pros and cons to each.
We all know what we individually like to use, and no one way is more right than another, so long as you have the right spectrum of lighting and ahve the effects you want to achieve. What I mean by this is I will always have MH as part of my lighting becasue I like the shimmer. Other run strictly T5 becasue they feel they get better cpntrol of light kelvin value or efficiency, and many combine the 2 to try and get the best of both worlds.