Fiddler,
Lots of wreck diving along the Atlantic coast and one or two at the mouth of the Chesapeake, but haven't heard much about diving Upper Chesapeake (north of the Bay Bridge) at all. Probably not the best diving, but okay for practicing... There's a dive shop in Annapolis. and a bunch north of Baltimore (Aberdeen, White Marsh) that might be able to give you a better idea of what's around the area. I would imagine they make the 2hr drive to the NY/NJ/DE coast.
If you're on the Eastern Shore, rent a kayak from somewhere like Rock Hall and snorkel around the inlet and coves. Hell, bring a tank and make a dive out of it! Be careful of the boat traffic, and bring a line cutter.
If you're interested in exploring, let me know. I'm in N. VA, but a drive out to the Eastern Shore is always nice... probably want think about next season unless you've got a drysuit. If you'd like addresses / numbers to some of the shops, I can dig them up.
Good luck and let me know what you find!
Ken
PS- If you're in the DC area, there's a place called Millbrook Quarry that the locals frequent. It's about 20-30 miles outside of DC. If you're looking for a dive buddy, drop me a message.