I watched the vice-presidential debate a couple hours ago. I'd say it's good news, just because no news is good news.
Obama is calm and cool under pressure (see his debate), eloquent (see his nomination acceptance speech), and wonkish (see the policy focus in his debate and his acceptance speech.) Biden is competent and experienced (see this debate), albeit a bit... unfocused (see his gaffes). McCain is belligerent in both personality and policy, (temper problems, objecting to meeting with Zapetero), erratic (suspending his campaign or not), and all talk (maverickmaverickmaverick). Palin is a moron (see the Katie Couric interview). Unless something unpredictable happens, all of this will continue to become more clear and obvious as the campaign goes on over the coming month, which is good for Obama.
Thursday's debate, just like the one between Obama and McCain a week or so ago, contained few surprises. Neither candidate lost his or her temper on stage, neither candidate said something that was obviously ridiculous, etc. If the debate doesn't change anything significantly by itself, that leaves trends intact, and those trends are good these days. No news is good news.