Drop ceiling is definatly nice for future mods, but, and this is a big but, do you really want to hear the whole ceiling rattle every time a big bass scene comes up in a movie. Plus you mentioned that your ceiling will be 7', a drop ceiling will lose you another 3-4 inches. No big deal if your 5 feet tall. Just wire for everything before hand, I mean everything. More than you ever think you will need. The cost is so minimal during construction, quadruple it if you forget to do it now, and want to do it later. I'm running into that now with mine, forgot to run for a projector.
ahh yes ripping out that Paneling is quite fun, that stuff really likes to splinter though. looks good man, its alot of fun getting started on a theater, knowing how much fun its going to be when your done is a driving force in the construction. as far as drop ceilings go I dont like them one bit, Just plan ahead and try to have any future things already ran. I built a soffit around my theater so worst case scenario I can cut into that and have minimal patch work. good luck with your theater, im still buildin mine too, I wish I knew about electrical, I can do everything else but electricity I just dont get, luckily one of my good friends is an electrician