And GOP incumbents in Georgia (Paul Coverdell) and Colorado (party-switcher Ben Nighthorse Campbell) are worth watching, though their opponents are less than intimidating.

CNN: Senate Overview

Ben Nighthorse Campbell of Colorado moved from the Democrats to the Republicans after the Senate defeat of a balanced-budget constitutional amendment, which he favored.

CNN: Party switching comes with political risks

Matt Fong in California, or Ben Nighthorse Campbell vs.

NPR: Democrats To Pick Up 4 Senate Seats �� At Least