So how did Dems fare in the House races? Dems have made a net gain of 19 seats so far, with a few races still too close to call.

The big Democratic gains were largely fueled by Barack Obama's successes in expanding the Democratic coalition across the country. These shifts were driven by increased minority turnout, as well as growing Dem margins among groups like Hispanics, blue-collar and college-educated whites, and suburban voters inclined to vote Republican in local races but who turned Dem because of the economy.

For example, Democratic gains among Hispanics may have been decisive in House pickups in Arizona, Colorado, New Mexico and Nevada, and economic jitters did a lot to unseat GOP incumbents or pick up open seats in Alabama, Florida and Pennsylvania, among others.

Our rundown on the state of play in the House races is after the jump.

• The Dems defeated 13 GOP incumbents: Marilyn Musgrave of Colorado, Christopher Shays of Connecticut, Ric Keller and Tom Feeney of Florida, Bill Sali of Idaho, Tim Walberg and Joe Knollenberg of Michigan, Jon Porter of Nevada, Randy Kuhl of New York, Robin "Liberals Hate Real Americans" Hayes from North Carolina, Steve Chabot of Ohio, Phil English of Pennsylvania, and Thelma Drake of Virginia.

• The Dems also captured 10 open GOP-held seats, in races declared so far: The open seat of Rep. Terry Everett of Alabama, Rick Renzi of Arizona, Jerry Weller of Illinois, Jim Saxton of New Jersey, Heather Wilson and Steve Pearce of New Mexico, Jim Walsh and Vito Fossella of New York, Ralph Regula of Ohio, and Tom Davis of Virginia.

• Four Democratic incumbents went down to defeat, all of them freshman gains from 2006 or in one case a special-election pickup: Nancy Boyda of Kansas; Don Cazayoux of Louisiana, Nick Lampson of Texas, and the scandal-plagued Tim Mahoney of Florida. No other Dem-held seats were lost to the GOP.

That brings the Democrats to a net gain of +19 so far, with a few more seats still up in the air:

• It appears that Rep. Virgil Goode (R-VA), best known for denouncing the election of Rep. Keith Ellison (D-MN) as the first Muslim Congressman, may have been defeated in a huge upset. With 100% of precincts reporting, Democratic challenge Tom Perriello leads by 561 votes.

• Rep. Dave Reichert (R-WA) is locked in a tight rematch with his 2006 opponent Darcy Burner. With 41% of precincts reporting, Reichert leads by 881 votes.

• In the open deep-red seat of Rep. Wayne Gilchrest (R-MD) -- a moderate who was defeated in his primary by right-winger Andy Harris, and then went on to campaign for Democratic nominee Frank Kratovil -- this race is still undecided. Kratovil currently leads by 900 about votes, which would make for a huge upset if it holds up.

• In the open seat of Rep. John Doolittle (R-WA), GOP nominee Tom McClintock has a narrow lead of 451 votes with 100% reporting.

Late Update: Since we first published this post, CNN and NBC have projected that Rep. Bill Sali (R-ID), who was originally on our list of close races, has been defeated. We have edited the post to reflect this.