Fifer's is similar to Anne Arundel seafood, but a tad more upscaley since there's a restaurant side. However, if you want to crack crabs on a picnic table covered in brown paper whilst chatting with people sharing a table with you, you can sit on the more casual side.
Tons of seafood, all steamed/cooked fresh to order. Then have an all-you-can eat, if you really want to throw down.
Echoing BontheC's sentiment regarding good seafood at non-seafood themed joints I heartily recommend East West Bistro. http://eastwestbistro.net/
Sushi is surprisingly good, the calamari is the best I've had just about anywhere, and they offer a wide ranging selection of authentic asian dishes as well as Americanized standards done at a much higher level than most Chinese restaurants. The shrimp in the Pad Thai are fresh, buttery soft creatures.
Service is impeccable when they're not mobbed, and reasonable when they are.
East West Bistro
8151 Ritchie Hwy, Pasadena, MD 21122
I'd say go to Anne Arundel Seafood.
A huge bar with just about any seafood you can imagine cooked to order. I'd stay away from their crab cakes (there are far better and larger in the area for cheaper) but their scallops and crabs are delicious. Steamed shrimp and soft shell crabs are also really good and reasonably priced. It's not fancy - some picnic tables with benches inside and outside and no servers, but it's a great place for seafood.
Sometimes you find the best seafood at a non-seafood house. Upscale: Trattoria Alberto (Italian but serves fish/seafood dishes) in Glen Burnie. Highly rated and delicious. Middle of the road suggestion is a chain, but appreciated nonetheless: Bonefish Grill. Big menu with all kinds of fins and crustaceans. Next suggestion is more down home and more like a diner - Greenhouse Grill- serves favorites like cream of crab soup, crab cakes and stuffed flounder.
6914 Ritchie Hwy, Glen Burnie, MD 21061
506 8th St SE, Washington, DC 20003
Well, it's probably not what your looking for, but I've liked all of the seafood-related dishes that I've had at Bella Napoli. I've never been but have been wanting to try out Anne Arundel Seafood. The Cheshire Crab is sort of ok, nowhere near great. You are looking for a restaurant, right? It's tough to tell from your question. But if your looking to buy fish and cook yourself, then I love the Allgreen supermarket on Rt 2.
350 Mountain Rd Ste E, Pasadena, MD 21122