They joked about how cold the studio was and how Sasha and Malia, when they reached the age for dating, would be surrounded by men with guns. The political performance on a talk show, once a rarity, is now a semiregular event--although Letterman noted with bitterness that George W. Bush never came on the Late Show. Nothing Obama said was particularly new or different, but if you're not used to watching Obama at length, you had to be impressed, I think, by his sheer confidence. Television is kind to the tall and thin, and that's Obama, who exuded a quiet comfort if not the sheer enjoyment that marked some of the other famed Letterman appearances like those of Bob Dole or John McCain, who Letterman also slobbered over, as well as Al Gore who famously smashed an ashtray on the show, complete with goggles, to show the idiocy of government regulations governing such things.
Did health care get a boost? Probably, a bit. Any time the president gets some space to try and reassure people he's bound to be better off. I know there's wariness of Obama being all Eurosocialist, but I thought he did a good job with one of his central arguments: No other people in the developed world has to live like this--in total fear of bankruptcy, wondering when and if they'll get reimbursed, afraid of getting fired and what it means for their health insurance. He needed more Hope, more describing what this world would be like. But as it went, he did fine.