Why does Virginia have so many possible Presidential nominees?

[retromike22]

In 2008 we had former Governor Jim Gilmore, although his campaign was pretty much a joke. Before Macaca 2006, George Allen was considered a likely 2008 candidate.

In 2008 you had Mark Warner being considered, and Governor Tim Kaine and Senator Jim Webb being possible Vice Presidential nominees.

Now in 2016 some still consider Mark Warner and Tim Kaine a possibility, but more likely Bob McDonnell is attracting attention. So the last 5 Governors of Virginia have been discussed as possible national candidates.

Is there something about Virginia that makes its Governors and Senators more likely to be considered Presidential candidates than other states?

1. Is it that "Mother of Presidents" nickname?

2. Is it because, being so close to D.C., more Washington pundits are aware of Virginia politics? Maryland politicians (with exception of Martin O'Malley) doesn't seem to attract as much attention.

3. Or is it because Virginia is currently a swing state?