An end to illegal torture of terror suspects. A beginning to a saner method of detaining, trying and convicting terror suspects.
Adept handling of the worst financial crisis and recession since the 1930s, leading to a profitable bank bailout (excluding Freddie and Fannie) and a return to growth. Check.
Salvaging of the automobile industry, which is now showing signs of life.
Passage of an ambitious stimulus package that has helped repair many crumbling parts of the US infrastructure and poured money into green industry.
The biggest social policy reform since LBJ - guaranteeing access to health insurance for all Americans.
Financial re-regulation of an out-of-control Wall Street, and the beginnings of real scrutiny (see Goldman) of the self-serving corruption at the heart of the financial industry.
Repaired relations with Russia, leading to a new START treaty, and better relations with China, leading to a revaluation of the yuan.
Joint Chiefs' endorsement of ending Don't Ask Don't Tell.
A tough re-balancing of the US position in the Middle East, away from the Likudnik-oriented jerking knees of the last eight years, and an assertion that US foreign policy should be conducted to advance the interests of the United States, not the interests of a belligerent faction in a foreign country.
The first point is very much debatable, and most of the others came with significant compromises, but this is still a pretty remarkable list of accomplishments.