6. Rep. Jeff Denham, R-Calif. An acolyte of House Majority Whip Kevin McCarthy, Denham didn't face much Democratic competition last year, running in a safely Republican seat. But with one of the Democrats' star recruits, astronaut Jose Hernandez, challenging him in a redrawn district, he'll need to raise all the money he can. He's off to a good start, bringing in $321,000.
7. Former Missouri Republican chairwoman Ann Wagner (R). Wagner was one of the top Republican fundraisers , raising an eye-popping $532,000. She easily outpaced her GOP rival Ed Martin, who raised only $115,000. And if Rep. Russ Carnahan, D-Mo., decides to run in the Second District, she will start out with a significant cash-on-hand advantage against the congressman, with $857,000 in the bank to Carnahan's $393,000.
8. Rep. Jason Altmire, D-Pa. Anticipating a redistricting-fueled primary matchup against Rep. Mark Critz or Rep. Mike Doyle, Altmire stepped up his fundraising game, big-time. He brought in $388,000 for the quarter, comfortably outdistancing Critz's $308,000 haul. Altmire has already survived a tough year for his party, and his fundraising shows he's well-equipped to handle new challenges ahead.
9. Iraq war veteran Tammy Duckworth (D): This Democratic primary in Illinois's 8th District could end up being one of the priciest in the nation. Duckworth raised an impressive $478,000, with the backing of Sen. Dick Durbin, D-Ill., and top Obama strategist David Axelrod. But her primary opponent, former Deputy Treasurer Raja Krishnamoorthi, isn't going quietly, and he brought in a solid $313,000 this quarter.
10. Oregon state senator Suzanne Bonamici (D). Bonamici's eye-popping fundraising numbers suggest she's the frontrunner to succeed former Rep. David Wu in Oregon, and two internal polls she's released show her with a sizable lead. She brought in $600,000 in the quarter - including a $200,000 personal loan on the final day of the quarter - but even without that she's easily outdistancing her two Democratic primary rivals. Republican businessman Rob Cornilles also raised an impressive $505,000, but he still faces a tough challenge in a Democratic-friendly district.