This independent thinker from Maine shakes off pressure to run with the pack. Collins and five other Republicans recently signed a letter opposing drilling in the Arctic National Wildlife Refuge, in an attempt to block this unpopular legislation from being tacked onto a spending bill. She also reliably fights attempts to weaken the Clean Air Act (in fact, she's said it should be strengthened). Now, as chair of the Governmental Affairs Committee, she's overseeing consolidation of the Homeland Security Department -- where she'll need to make sure that taxpayer money is spent without waste and that the nation's chemical plants are truly safe from terrorist attack.