Well it would certainly help us a lot to carry Virgnia. But, loosing Virgnia is not necessarily the death nail to our chances either.
It would make it much more difficult for the GOP
Start at the 2008 map with the new 2012 elector distribution
Indiana to the GOP - Dem Wins
Now change North Carolina - Dem wins
Also change Florida - Dem wins
Move Colorado to the GOP column - Dem wins
Now recolor Ohio - Dem wins
That Nebraska electoral vote, move it to the right - Dem wins
Now the Dems have 276 and they could still lose Iowa or New Hampshire or Nevada. However if the Dems win Virginia the odds of them losing Nevada, New Hampshire, Iowa, Wisconsin, Pennsylvania are minimal-to-none