In my experience the best fresh fish to be had at the chain grocery stores is farm raised rainbow trout, and the best from the environmental standpoint also. I'm no enviro wonk but I love to fish and being from south south Alabama I largely try to support sustainable fishing. It, farm raised catfish, and farmed striped bass (actually hybrid striped and white bass) are your best bets if you are inland because they are probably being farmed inland and closer to your location. Farm raised salmon is OK, but seems to be a little lacking to me.
Like THS said, if it smells like anything other than the beach, buy the pork chops or buy frozen. Oh and never buy farm raised shrimp (wife and I got sick off some one time). And when it comes to shrimp, crawfish, and crab, even if you buy it "fresh", it has probably already been frozen at one point anyway (def true with the crab).