Sorry, I haven't been checking back here lately. I set up the tank with 150lbs of live rock. 100lbs of Fiji and 50lbs of Manano (Indonesian). Since then I've moved some to the two refuguims but most of it is still there.
I don't believe there is any amount of live rock that is necessary for any tank. It really depends on what kind of setup you prefer. Depending on the quality of the rock you will get more "life" with more rock but all of it won't necessarily be desired. If you have a live deep sand bed with fine sand and keep it well stocked with sandbed critters (pods, worms, sand snails, etc.) you don't need any rock but then where would you put your corals? Too much rock can prevent adequate circulation and leave less swimming room for fish if you have the type of fish that are open swimmers.
Hope this helps!