Many of the districts where Obama won or came very close and that are currently uncontested by the Democrats in 2009 are in key swing areas in Virginia where the Democratic tide washed farthest in 2008. These districts are in Virginia Beach and the far exurban reaches of the Washington D.C. Metro (Fauquier, Loudoun, the farthest reaches of Prince William Counties).The only thing I'd add to this analysis is that if you're going to be in a fight, you need make sure you've got a strong, well-funded candidate. If you've got a really weak, poorly funded candidate, the danger is that all you'll accomplish is driving up turnout for the other side or even hurting the top of the ticket. So, yes, contest every race...with strong, well-funded candidates.
Virginia Democrats (I know, because I’ve spoken to them) come up with cogent reasons as to why this or that Republican incumbent is too tough to be taken down. But the fact of the matter is you can’t win the fight if you’re not in the fight. If a scandal involving a Republican incumbent should arise in one of these districts between now and the November election, the Democrats won’t even have an alternative on the ballot whom people can turn to. (And of course it’s also bad for the democratic process to have unchallenged elections.)
The second article is from yesterday afternoon, entitled "Does History Dictate That New Jersey and Virginia Will Elect Republican Governors in November?". The argument here is that "there are a lot of reasons to be skeptical about predictions that New Jersey and Virginia are somehow destined to vote Republican this November" because Democrats control the White House (and Virginia supposedly always does the opposite). In fact, according to 538.com, "there's plenty of evidence explaining why one party or the other has won Virginia gubernatorial elections without resorting to the 'White House backlash' explanation." I tend to agree, although certainly it was an advantage to Democrats being able to run against Bush the past few years, to argue that Bush=Kilgore or that George Allen voted 96% of the time with Bush. We don't have that anymore, but on the other hand we still have plenty of people to run against - Rush, Newt, Cooch, Eric Cantor, Bob McDonnell himself, etc. As long as they keep opening their mouths, we'll have plenty of material to work with. :)