One race I've overlooked is the tight race in the Oregon Fifth Congressional District which pits first-term Democrat Kurt Schrader against Republican state legislator Scott Bruun. This district in northwestern Oregon is almost perfectly purple; it voted for George Bush in 2000 and 2004 and Barack Obama in 2008. The Fifth has sent Democrats to Congress for over a decade and Kurt Schrader cruised to victory 54% to 38% in 2008. He's reliably liberal; voting for the stimulus and, after seriously considering voting against ObamaCare, decided to vote for it.
His challenger is GOP state legislator Scott Bruun, a forty-four year old businessman from Portland who is a lifelong Oregonian. Bruun believes he's got a good shot at winning the seat and is trumpeting a recent poll that puts him up 41%-38%. A photogenic candidate with a young family, Bruun is running a straightforward and simple conservative campaign to contrast himself with the liberal Schrader and I think he's got about an 80% chance of flipping the seat.
It will be hard enough for Democrats to hold on to GOP leaning seats (around 50) but will have to defend purple and light blue districts of which Oregon CD 5 is a typical example.