In Virginia, if Mark Warner runs again then the Democrats should retain the Governorship easily regardless of who the Republican nominee is. And I don't regard George Allen as a strong candidate, in fact I think if he runs again then the Democrats will have an advantage. Apart from Warner, a potentially strong Democratic candidate could be Creigh Deeds, who lost very narrowly for Attorney General in 2005 by 323 votes.
Mark Warner I think has his eyes set on a Senate seat now, Since John Warner could be retiring, Although that is still very unclear at the current time.