I could not agree more with really researching where you live. I have been to most big cities in the U. S., and some very unsavory parts of NYC, LA, New Orleans, etc, and have never been more uncomfortable then when we (accidentally) ventured into a not-so-safe part of DC. I think that has been the only time I've been flat-out scared of my surroundings. I wasn't even comfortable when we were in the car, and not just walking sometimes.
Housing is quite expensive in the area, so you'll really want to make sure your DH is getting a salary that you can afford housing. It isn't just the posh areas that are expensive, it is the average-but-safe areas, too. Though it isn't as bad as California or NYC, it is definitely something to keep in mind.
That being said, there are really lovely areas in the city, and we felt very safe and comfortable walking them at all hours of the day. Many of the suburbs are lovely, too, and I especially loved Virginia right across the river. I wish we had had more time to explore that area, it was beautiful, quaint, and people were so friendly.
I seem to remember when we were there, that the people who lived there complained a lot about how high the taxes were in the area, and a quick Google seems to back up that memory. It looks like taxes are a lot less in Virginia than Maryland and DC. A lot of things that aren't just basics, like going out to eat, is taxed at a much higher rate than the sales tax.
Can't say much about the rest, I'm American, not an expat.