Basically I go to them all. (Except Petsmart or whatever that big pet store is.) I am partial to The Aquarium in Old Town, and Sea Dreams. I have never bought fish from The Cove, but I have gone in there for parts. I get most of my info here.
Sea Dreams has got some great live rock, but kinda pricey. But I got lots of creatures on it too. If your looking for fish, you just have to make sure they look healthy. And ask your questions here before you go!!!