Hmm, I tried looking at IBMs website but can't really tell where in the dc area they are located, therefore where he could be at. Without knowing more, it might be hard to identify the best areas to live. One place could be 20 or 90 min from work...
Centerville, Fair Lakes/Oaks is more affordable than other places, but the commute could be terrible if he needs to travel on 66 headed East toward dc. But, if you want to stay in the near burbs, you'll probably get bigger house for your buck here.
Reston is nice, and slowly becoming more affordable. The schools in Reston are generally good, I've heard good things about Armstrong elementary. There is a townhouse in my subdivision that is now listed around $330K, which I expect will sell for near $300K. These are 1500 sq ft, approx. I'm not sure if that would be too small for your family.
Herndon is going to be even more affordable, but I do not know about the schools. Without going pretty far out in the Nova area, you may have a hard time finding a single family home in your price range.
Reston and Herdon are both close to route 7 and the 267 toll road. These both offer an easier commute East than the 66. Although the toll road will add to your cost, and the 7 can get kind of hairy. Eventually, I expect there will be metro here, but that will be a decade down the road. There is a Whole Foods in Reston, and a Healthways in Fairfax (not too far). There is also your Target, a YMCA and numerous other grocery stores.
Ashburn is further west than Herndon, and is, if I recall, just as pricy, so I think it would only make sense if he's actually working there, or somewhere in the dulles corridor. (reston, herndon and sterling are all along the dulles corridor). Although, someone else should pipe in on Ashburn.
Springfield and Burke will likely be less expensive. I don't know too much about these areas or their schools. However, if your DH has to commute going north on the 95 to get to work it could be a really sucky drive both to and from work, depending on how far north he needs to travel (although, I'm not sure if it would be more than an hour).
I am sure someone else will be able to come on and talk about areas to find other homes in the area.
Also, I can't talk to Alexandria or Arlington, both of which have access via metro, but I don't know about affordability or schools. I would have liked to live in Arlington (Ballston, Clarendon, or even Virginia Square), but when we were looking, prices were out of this world.
If I think of more I'll be back. Good luck in your search!