Look into western Prince William (Haymarket) and Fauquier County (The Plains, Marshall, Linden). It's MUCH nicer than it is around here and it's only 15-40 minutes further west.
You know, I find it sad when I see people talk about how it's "only" 15-40 minutes farther away.
About 5 years ago, my parents moved from NoVa to Spokane, Washington. My father's commute (distance-wise) didn't change much. However, because of the difference in traffic, what used to take him 45-60 minutes now takes him only 15-20 minutes, and I can see the difference it has made in his stress levels and overall health. (Admittedly, some of the reduced stress comes from having most of his grandkids around.)
Even a 15 minute difference in your commute each way steals about 120 hours of time that you could be spending with your family each year. An extra 40 minutes each way increases that lost time to almost 320 hours, or almost 2 whole weeks (13 days, 8 hours). When I bought my house two years ago, I made the switch from a 1 hour commute (by bus, train, and foot) to a 15-20 minute commute each way (by car, including picking up a coworker). Even in the worst snow storm this year, I still got home in 1.5 hours, while my boss (who lives "only" 30 minutes farther away) took 11 hours. You couldn't pay me enough to go back to that longer commute. I would never even consider a commute like one coworker (who lives in West Virginia and commutes into Arlington and/or DC every day).
For the most part, Northern Virginia is relatively low crime all over. Yes, there is some variation from place to place, and there are some places you want to avoid, but none of it is so bad that you need to consider losing so much of your limited time just to avoid crime.
Also, for the most part, pretty much every jurisdiction in NoVa is fairly friendly to carry, both OC and CC. It gets a little worse the closer you get to DC and the Potomac, but even then, it's not too bad. I've been carrying all over Fairfax, Arlington, and Alexandria without any significant problems for several years.
Of course, you need to decide for yourself what trade offs are worth making. If you are willing to accept a longer commute to get a bigger/cheaper house, or avoid a slightly increased crime rate, then go for it. Just keep in mind both the benefits you will be getting and the disadvantages that come with them.
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