John Podesta (former COS to Clinton) indicated that Obama might consider "using his executive authority to change stem cell and oil-drilling policies without waiting for congressional action." This means that we could start to reverse the Bush administration's ostrich-like posture toward knowledge in general and science in particular. Doing this in the first few days (hell, he could have the EO drafted tomorrow, ready to sign on Day 1) would send a clear signal to the country that we're really going to shift gears.
See also this WSJ piece, which notes that "[r]olling back executive orders issued by the Bush administration could give Mr. Obama a fast way to put his mark on policy making after he takes office, as past presidents have. Other Bush-era executive orders that Mr. Obama could reverse include a ban on federal aid to family-planning organizations that counsel women on abortion, and a decision in December that restricts California in regulating greenhouse-gas emissions from cars."
In addition to being a powerful signal of "change," addressing Bush's boneheaded obstruction of California's efforts to clean up the environment could actually bring material change to the country. If "conservatives" really believed in letting individual states act as "laboratories for democracy," they would not have stood in the way of efforts like California's. Perhaps Cali will begin to show some progress, which could stir up some popular support for Obama's plan to create 5m new "green jobs." The Center for American Progress thinks this is very doable.
Emanuel Urges Aid for Auto Industry - NYTimes.com