Congressional Quarterly has a nifty map-based feature that lets you see the match-ups for U.S. House, Senate, and governor around the country and how CQ’s analysts see the races at the present time. By the way, they’re forecasting little net change in the Senate, a Democratic gain in the House (but they’d have to win virtually all the toss-ups to take the chamber), and an almost-certain gain for Democrats in the governors races (though many of the latter don’t have useful polling or clear candidate match-ups yet).