South: 21 seats (1 AL, 2 AR, 4 FL, 1 GA, 1 LA, 2 MS, 1 NC, 1 SC, 3 TN, 2 TX, 3 VA)
Northeast: 14 seats (2 NH, 5 NY, 5 PA, 1 NJ, 1 MD)
Midwest: 14 seats (2 IN, 3 IL, 1 MI, 5 OH, 2 WI, 1 WV)
Great Plains: 5 seats (1 KS, 2 MO, 1 ND, 1 SD)
Mountain West: 5 seats (2 CO, 1 ID, 1 NM, 1 NV)
West Coast: 1 seat (1 WA)
[59 seats - a few more weren't finished when I made this]
A wave election, but a regional tide.
The West Coast more or less fought off the Republican tide entirely.
All of New England except NH resisted the Republican tide, and in the Northeast only NY and PA saw any significant Republican signs (with the MD seat one that was a fluke pickup last time) - which came nonetheless in more Republican areas of both states. Maine may have seen a right-wing governor emerge but only as the beneficiary of a split left. New Hampshire will very likely produce a massive swing back in 2 years, especially if Republicans put up an unappealing candidate for president and if state Republicans overreach. Several of the NY and PA seats should swing back in 2012, though Republicans will have at least some voice (or lots of control) in both redistricting efforts.
The midwest was harsh, with widespread significant losses basically boiling down to the poor economy. Seats in Michigan, Illinois and Wisconsin are probably going to be tough holds for Republicans in two years, plus at least a few in Ohio. These are all very swingy. Republicans have control of lots of redistricting efforts, too, making many of these seats harder to regain immediately.
The Great Plains are a deep dark red anyhow; a handful of gravity-defying seats toppled. The only reasonable Democratic recoveries here would be in Missouri, but that state has also been edging rightward as the cities suffer from the economy and the surrounding rural areas suffer relatively less. Doing anything with the big empty states is a long-term project. These states used have 'prairie populists' but have in effect given up and settled for being afraid of anything changing instead of trying to make anything better.
The mountain west does not have a lot of Democratic representation other than Colorado and New Mexico, both of which did reasonably well in holding on. The Arizona 'papers please' law helped Reid solidify the Hispanic vote behind him and should pay off for Democrats for years to come, making recoveries in Colorado, New Mexico, and Nevada very plausible, and future gains in Arizona. The whole region is probably going to come down to the Mormon birthrate versus the Hispanic birthrate, demographically.
The west coast hung completely tough, with only one swingy seat flipping. The whole region seems to have pretty well settled out, politically, but we'll see what California does with its newly-mandated redistricting commission that may eliminate the incumbent-protection racket going on out there. California, Washington, Oregon, Hawaii, and Alaska all pretty solidly demonstrated commitment to their current political alignments.
And then the SOuth. That pretty well does in the remaining southern democrats outside of majority-minority districts. Florida, Virginia, and North Carolina may return some of those gains in a better year, while Texas continues to face Democrat-friendly demographic shifts (but gave Republicans major gains in the state house, while making no changes in the state senate, so Republicans will have near-total control over drawing the lines again). The flipside is that with an already Southern-heavy caucus, Republicans are even more Southern-dominated now; this creates more of a feedback effect, encouraging them to be more dismissive of other regional sensibilities and making northeastern and midwestern Republicans more likely to be left hanging.
Party Influences
Democrats are very much the party of minorities in the Confederacy now, with the transition close to complete at this point. There aren't many Republican gains left to make south of the Mason-Dixon line without making inroads into minority votes. That still leaves Democrats with a reasonable Southern wing, but one that is by and large urban. The redneck vote has spoken, loudly, angrily, nonsensically and inarticulately. There are not enough Southern cities to make up for the large rural populations. Virginia has enough growing influence from DC and growth in Richmond to be increasingly viable, while North Carolina's Research Triangle is also getting large enough to keep the state in play. Florida also has significant urban areas. Otherwise, forget the entire quadrant.
Democrats are similarly cemented in place in most of the northeast. New Hampshire is prone to extreme fluctuations, with two 100+ seat shifts in the last four elections, all depending on who shows up. Otherwise, the only regions that give Republicans any chances are midstate Pennsylvania and upstate New York, both of which swing on economic concerns, and both areas that are losing population in favor of the cities in those states. The northeast is heavily urbanized by American standards and is thus fertile territory for Democrats.
Similarly, the west coast and mountain west appear to be pretty well consolidated for both parties, with clearly delineated areas of Democratic control and Republican control. Colorado is very divided along partisan lines, but with Democrats holding an edge that has become increasingly distinct. Nevada is closely contested but the increasing Hispanic population augurs well for Democratic growth there. New Mexico is friendly but contested territory; Arizona is unfriendly but positively trending. Utah, Idaho, and Wyoming are more or less impossible bastions of "I'm a self-made man so give me my government subsidies" crazy conservatism, all unlikely to change much without major development of urban centers (like the D-friendly Salt Lake City in Utah). Basically, Colorado has Denver, New Mexico and Arizona have a couple of urban centers, and Nevada has Las Vegas, and those cities make those states winnable. Utah, Wyoming, and Idaho have no comparable urban areas with large enough percentages of state population. I'm pessimistic about Montana for similar reasons; just not enough cities.
The great plains are the same story. Too much rural, not enough city. There's much less minority presence to mitigate this, making the Great Plains a more or less unbroken wall of cultural conservatism. The only way to jolt the region out of its fear of change would be to wipe out farm subsidies - THEN let's see who favors government interventionism. Hey, they wanted Rand Paul, let's give 'em what they wanted.