Dem Congressional Challengers
Those 3 seats (along with JoAnn Davis in the 1st) are virtually unbeatable. The districts are conservative enough that nothing short of an arrest would cause these people to lose.
Anyway, from a strategic prospective running someone here is stupid as well. If Harris Miller or Jim Webb is going to beat George Allen, they are going to do it in NOVA and Tidewater. They will need huge margins in those areas and need Allen to get small margins (and turnout) in the more conservative rural areas and the Richmond suburbs. In order to do this, they will need to prevent high turnout in those areas by not challenging the congressmen there. No one is going to beat Goodlatte, but if someone runs against him, the district will vote in droves to ensure he wins. Most all extra votes in the 6th will likely be George Allen voters. Same goes for the 7th and the 4th. I would even argue that not challenging Tom Davis and Frank Wolf would be a good idea. That way GOPs wouldn't go vote to ensure those guys won, but dems would be voting for Miller/Webb.
The dems now think they are world beaters and can win every race, and that mentality may be what prevents them from winning some big races this year.