I'm glad to hear your job hunt has been successful, 10000li! We're actually about 3 hours west of Baltimore ourselves. I don't have much experience with the DC/Balto area, but it's very...erhm, urban and cosmopolitan. Some people thrive in that environment, but as a country girl, I don't feel comfortable there. Also, being so close to Washington, there are LOTS of laws to abide by.
The area can be very beautiful. Maryland is on the North-South divide, so you'll get an awful lot of differing opinions regarding how the world ought to be run. I'm sure you'll do fine with that! ;)
Yes, the humidity can be atrocious, but that's why Carrier invented the air conditioner. :)
You'll be within striking range of some lovely beaches, too, and going the opposite direction, some lovely mountain areas--although you'd probably consider them mere hills.
Anyway, best wishes on your new job, and I hope you & your family enjoy your new home!