Fairfax Co. is huge. Where in Fairfax is the job?
My suggestion is to live close to your job. Traffic in northern Virginia is a nightmare if you have to drive on any of the highways to get to work.
Arlington is large and hodge-podge. Notice there is no city in Arlington Co. It is the left over rump of the Virginia side of the District of Columbia. You can see the straight boundaries still show the original DC diamond. It is an amalgamation of many, many housing developments. In the '30s, the post office threatened to withhold mail delivery because the streets were so confusing. Pre-mapquest, driving in Arlington was a logistical nightmare. Every one of those housing developments had a main st, and an elm st, and an oak st, etc. So if you had to go to Oak St, you had to figure out which Oak st. And a street with one name can be in 4 separate pieces! It's unbelievable!
Needless to say, I don't drive much in Arlington. Here is one place that is very nice and near the metro. But you are going to have a long commute if you live here and work in Fairfax....if you can make connections to get from point A to point B even.http://www.riverhouseapts.com/