The Washington Post has put together a nice table dividing key Congressional races into a series of categories based on the key issues in each one (example: "Anxious Suburbs » Will the Iraq War come home in November?"). Definitely worth a look.
I am an assistant professor in the Department of Government at Dartmouth College. I received my Ph.D. from the Department of Political Science at Duke University in 2009 and served as a RWJ Scholar in Health Policy Research at the University of Michigan from 2009-2011. I also tweet at @BrendanNyhan and serve as a contributor to The Upshot at The New York Times. Previously, I served as a media critic for Columbia Journalism Review, co-edited Spinsanity, a non-partisan watchdog of political spin, and co-authored All the President's Spin. For more, see my Dartmouth website.