As NLS told us, NOVA and its "exurbs" will gain almost 2 seats in the Senate in 2010. These 2 seats will come from no particular area downstate, but the biggest loss areas will be inner hampton roads, southside and southwest.
The first likely seat change will be along the "northern neck". It looks like Chichester's 28th district will lose Stafford County and gain Essex, Middlesex, King William, King & Queen and Glouester Counties along the Bay. This will then push McDougle's 4th district seat back to just Hanover, Caroline, part of Spotsylvania and maybe New Kent and/or Henrico. Ed Houck's 17th will then stay the same (athough the GOP would probably try to draw Houck out of the district), creating a new district anchored by Stafford County with Fredericksburg and a small piece of PWC finishing out the 200k people. This seat will likely go GOP as Stafford County still seems to be a GOP stronghold.
NOVA will be the site of the second new seat, but its hard to say how exactly it will be drawn. Much of this depends on who is in what seats come 2010. Russ Potts' district will probably lose Fauquier County, freeing it up to help prop up other NOVA seats, unless Jill Holtzman-Vogel is the Senator there. If she is the Senator, Loudoun will likely only be a small sliver of the district while most Fauquier would fall into the 27th. If Mark Tate or someone other than Jill is there, Fauquier will probably be eliminated from the district, giving more of Loudoun to the 27th. This then spills over into the rest of the seats.
Loudoun will have to have at least 2 seats partially within the County. If Mark Herring is still in the 33rd, we could see a seat that takes all of Fauquier and most of Leesburg (excluding Herring's house) while the 33rd would basically lose the western part of Leesburg while gaining a small amount of Fairfax. This would hopefully result in another GOP seat. Another possibility is to draw a Leesburg based seat totally in Loudoun County, which would then dump the eastern-most Loudoun precincts into a Fairfax seat. This would probably only happen if a GOP is back in the 33rd, and if they are from Leesburg (or the surrounding area).
In Prince William, if O'Brien is still alive look for the map drawers to give him a bigger portion of PWC as his base and pull him out of his weakest Fairfax precincts. If Cuccinelli is gone, they may destroy the 37th and give O'Brien the strong precincts and make a "new 37th" with the east Loudoun and west Fairfax precincts that would be left over. The other part of PWC will still be a 29th that keeps Manassas and loses the weakest precincts in the south to the new Stafford seat or the 36th. They could even use Fauquier to prop up a PWC seat, but as I mentioned eariler, its all about where everyone is.
In Fairfax, there are alot of scenarios. JeanneMarie, Cooch and O'Brien could all go down in '07, they could all survive, or a combination. If all three survive, the map drawers will just do their best to divy up the strong Fairfax precincts among the three seats. If all three lose, they will probably try to draw a GOP 39th and a dem 34th and 37th. This is also the scenario if only O'Brien survives 2007. Currently, Cuccinelli looks the most vunerable in '07. If only he loses, the 37th will probably be destroyed and give his stronger precincts to the 34th and 39th while his weak ones go into the western Fairfax, east Loudoun seat. If only Jeannemarie loses, her strong precincts will go to Cooch while her weak ones go to all the other dem seats. If only O'Brien loses (which I would say is pretty unlikely), his PWC precincts would be used in the 29th while his Fairfax precincts go to Cooch. Basically, Fairfax will probably be a nightmare for GOP drawers in 2010 unless they only need to draw themselves one seat (most likely O'Brien). Otherwise, the line drawers may have to draw 3 sub-50% districts just to keep them all competitive (depending on future trends here).
As for where the seats will come from, the GOP will likely try to elminate Roscoe Reynolds in SWVA if he is still there. This will be hard to do though, since the districts are already huge. The second downstate seat to be lost will probably be one from the current 3rd congressional district area. Even so, the 2 seats will be spread out over a large area, not pinpointed to 3 or 4 counties.
This will all result in a likely net change of zero. If the GOP loses all three Fairfax seats in 2007, they may be able to get the 39th back under this scenario. They also may be able to get the 17th and 20th into their column by drawing out the long running incumbents in those areas. Other than that, there probably won't be any major changes. Even so, just one seat may be the difference in who holds the majority after the 2011 elections.