If you are willing to have a longer (~20 mile) commute, the Reston area may be viable. There is decent bus service to the West Falls Church metro station from Reston Town Center and P&R lots at Whiele Ave@Rt 267 and Herndon/Monroe. The W&OD bike trail runs thru Reston enabling a long commute entirely on bike trail via W&OD and Custis Trails into Rosslyn and DC (especially Georgetown). There are also some express bus routes so you could bike one way and take bus the other. If you want to bring bike on Metro, get a folder - full size bikes aren't allowed during rush hour. BTW, don't believe anyone who says "Metro is coming to Reston" - they haven't turned a spade of earth yet and it's only going as far as the Whiele Ave P&R, if it even gets that far.
That said, if I was working downtown, I'd look first at the closer-in areas: Arlington, Alexandria, or Falls Church. Lots of good info at waba.org, bikewashington.org, and
www.fabb-bikes.org.