This area is not so great. I'm not sure how good the Severn River near you is, but I think some of it is salty and I hear about jellyfish (sea nettles) there.
I sadly use the Potomac, and keep my boat in Woodbridge at the Tyme n Tyde boatel (nice, but about $4k a year). Lake Anna is nicer, but crowded on weekends and at least another hour further south, with horrible weekend traffic (at least going on 95) unless you go early in the morning.
The Potomac can be good (calm, few boats) on weekdays, but by noon on weekends all the boats (including some very big ones) usually destroy what water the wind has not (lots of wide open water so the wind can really be a problem). The few semi-protected coves are mostly shallow and not very usable. Mattawoman Creek is the best protected cove-type area, but it's too shallow for decent wakesurfing or even getting a very good wakeboard wake, and it's small and full of boats (lots of tubers). I end up there way more than I'd like, out of desperation. The depth there rapidly fluctuates between 3-20 feet (mostly around 6 feet - the deeper parts are very tiny), so the wake size/shape is constantly changing.
Did I mention I want to get out of this area?
I'd be happy to take you out on the Potomac once it warms up a bit.
-John