Gee, thanks Rosita for the kind word. Yes, once lovemykribs finds this she will help the best, but, for now may I make some suggestions?
*First off, very cool that you are getting such a large tank! You have so many options. Personally, I like the sand in my tank for a substrate, the fish seem to really like sucking it into there mouths and spitting it out. I do have a little crushed coral mixed in but onlly like a handfull so you see it sticking out here and there. I did put a nylon stocking full of crushed coral in my filter though to buffer the water.
*And if you go with sand, buy the 50# bags of 30 grit from the hardware store for 3 bucks, its a lot cheaper than the lfs. And when you buy your rocks, get them from your local rockery/landscaping supply. They will have all the same rocks as the lfs but for 20 to 35 cents a lb. as apposed to the $2.00 a lb. the lfs charges. And seeing as you have such a big tank, you'll save a lot on decorating it. In fact they will most likely just give it too you if you get a little at a time.
*Anyways, what do you like? the haps and peacocks or the mbuna? You will probably have to choose between one or the other, unless you get some of the more docile mbuna like yellow labs, rusties, zebras. then you can mix haps with those. Also, the haps like more open water, wheres the mbuna dwell in the rocks and appreciate lots of rocks and caves.
* Hope this kinda helps get you started.
congradulations on the tank and be sure to post picks when it's all done.