I'm always in the market for another one as well... However, and for what it is worth, there are two of the larger chains on 20 across from the Mall of Ga.
Petsmart is on the 85 side on behind the burger king near the new costco. They carry no SW fish. However they have pretty good prices on dry goods from time to time. I just bought a 160 gallon bucket of IO salt for 44 bucks.
About mid ways between 85 and 985 (next to waffle house and also across from the MOGa.) is a PetCo. They have a small selection of SW fish and such. Some of their prices are OK some are pretty high.
Neither one will scare Aquarium Showcase or Capp Bay, but they are what they are.