Definitely depends what kind of lifestyle you want.
In 45 minutes you could be all the way into West Virginia! Where you could buy quite a big house or a big piece of land.
If you need good schools I'd recommend Loudoun County or Fairfax County. Loudoun has one educational disadvantage which is that school boundaries have been changing very often because of growth and kids have had to switch schools often.
Best bang for the buck housewise closer than West Virginia would certainly be Winchester, a nice medium sized town with friendly people but might be a little culture shock if you are a liberal politically. South of Winchester is the Shenandoah Valley and the northern part is also within a commute if you think you wnat more land or a reverview.
Loudoun has a rural west and a suburban east. Take your pick in Loudoun of winding rural roads and small farms or large subdivisions with plenty of shopping centers and future access to the subway coming someday. In Loudoun, Leesburg is the historical County seat that also has an outlet mall, Purcellville is an old farming town that's now a bedroom suburb, and Middleburg is still a horse-oriented very small town tourist attraction. Aldie is a very very small village and many homes that have an Aldie address are really in subdivisions east of the village, not in it. In the suburban area of Loudoun, Lansdowne, Ashburn, are well-known areas. South Riding, Countryside, Brambleton, are other well-known subdivisions. In your price range you will find both townhouses and single family, depending on the aREA.
Fairfax is more densely developed and definitely culturally diverse. Probably a bit less for your money in that some housing will be older and maybe smaller. The "named towns" in Fairfax are really indistinguishable from the surrounding sprawl. But individual neighborhoods can be very attractive. In general, you will probably want to look at Oakton, Vienna, Fair Lakes, or western Fairfax; some people liked the planned community of Reston.
Route 66 is a major highway commute route west. Routes 15, 29, 50 and 7 are multilane roads but not what you think of as highways. Route 7 gets quite congested. There is a toll road west from Dulles as well(Rt. 267).
There is lots of inventory now and many short sales and foreclosures in all areas. You will have a lot to choose from.