President Obama has told ABC News that he'd prefer to be a "really good one-term president than a mediocre two-term president."
Well, that's a pretty high bar. Our history doesn't have a long list of presidents who would be termed "really good." Look at C-Span's survey of presidential leadership. John F. Kennedy is ranked sixth. I suspect that a good part of his high rating is his handling of the Cuban Missile Crisis, probably not the Bay of Pigs fiasco. Obama has time to demonstrate his abilities in a crisis, but so far, his handling of the Christmas bomber does not inspire confidence. And there is nothing else in his handling of foreign affairs to give such confidence. If you count Truman and LBJ as one-term presidents given that they only faced election once, you'd have some more examples. While Obama has certainly tried to emulate LBJ on the domestic side, he wouldn't want to follow Johnson's foreign policy experiences. Probably, he would think the same about Truman.
You'd have to go to Polk to find a president regarded as a successful one-term president. Once again we have a wartime president. Historians will continue to argue about the justice of the Mexican American War, but Polk was a terrible commander-in-chief, interfering with the conduct of the war for crass political purposes to weaken Whig generals like Zachary Taylor and Winfield Scott. I suspect that Polk's expansionism isn't a model Obama would prefer to follow, though the political maneuvering behind the scenes is something I wouldn't be totally surprised at from this administration.
The ambition to be a very good one-term president might be fine, but he left out the third, and more probable option. He could be a mediocre one-termer. We've had a lot more of those in our history. And after Obama's first year, mediocrity would be an improvement.