Here's a bit of pre-election Obama propaganda in chart form, making the case that his domestic agenda has mostly been pretty good, if not the magical transformation some hoped for.
For me the policy that stands out as most worth saving are the pre-existing conditions ban and the coverage of 30 million uninsured under Obamacare. Mostly I want Obama to win so that those policies will come into effect in 2014 and won't be repealed as Romney has promised. More than the specifics of the law, the survival of Obamacare would signal the ability of government to actually make progress on the really hard problems facing the country (like health care), instead of just talking them over for decades on end. If Obamacare survives then it can be tweaked and improved, if it's repealed then all the political effort will have been wasted and we'll be back with the crappy status quo. The political repercussions of an Obamacare repeal would be enormous, to say nothing of the human toll.
In addition, whoever is elected will most likely get credit for the economic recovery. It would be crushingly unfair to see a President Romney take credit for Obama's tough, unpopular decisions.
After four years I am still mostly positive toward Obama. He hasn't been perfect. Some of his failures are his fault (such as the drone/terrorism fiasco), while others are the result of a broken Senate and a remarkably skillful and unified opposition. But he's pointed in the right direction.