The local walmart where I go to college (Farmville, VA) doesn't carry fish at all. It has an aisle of aquarium kits, food, supplies... just not the actual animals. This is good because it means no abuse, but bad because it's a VERY small town and walmart is pretty much the only place to buy *anything*, let alone aquatic pets.
When I'm at home (Short Pump, VA), walmart is the only place in town that carries apple snails. Their snail tank is similar to some I've heard described in this thread - mostly empty shells but some healthy looking snails hanging out at the water line. I got mine there and they're fine. Their fish tanks aren't as bad as some y'all mentioned... the odd goldfish carcass sticking to the filter in some tanks, but not lots of dead ones or sickly looking ones.
My petsmart's fish are fine. They don't carry snails, though, and that's all I'm interested in

This petsmart is barely a year old, if that, so maybe that accounts some for the (apparently) better than average conditions?
We've got this really cool little family-owned pet store called Perfect Pets. They've got a great fish section with all sorts of everything. You know the lionfish in Duece Bigelow? They've got one of those that follows you and stares at you when you walk past his tank. But they don't carry apple snails, again! I love that store, though, because they have a big cat that lives in the store and he loves me

and they carry small breed puppies on a regular basis now. They're sweetie pies. Today I was in there and they had a little bitty monkey... the sign said it was 6 years old so I'm guessing somebody couldn't keep it anymore and sold it to them. And reptiles get their own room in the back that's nice and warm.
I <3 Perfect Pets. They need snailies.
Moo