I have to agree with the comments on the Baltimore Aquarium. Definitely worth a trip. They have some awesome amazon river and region specific freshwater and brackish tanks. As far as marine aquariums they have a few open ocean tanks with larger fish, a caribbean tank with a sunken ship as the aquascaping, and one Indo-pacific reef tank (the only tank with live corals) which is around 1,000 gallons and pretty nice.
They have a really cool aviary on the top floor with all sorts of birds from the amazon rainforest with a few monkey's (can't remember which type) that are in there when the birds aren't nesting. They also added an entire Australia section on the second floor which is basically another aviary.
I know its not in the area by any means but if your ever in New Orleans check out their aquarium on the Mississippi river. Its about the same size as the one in Baltimore with more reef stuff.