If Obama were a really good Machiavellian -- and maybe he is, it's no insult -- I might think he released the Wright video into the wild himself. It had to out sometime - Obama had warned Wright a year ago that he might have to distance himself at some point. When it hit, Hillary had been taking a beating for going negative on other fronts, so her response was late and muted. It also came after McCain had taken a bit of heat for seeking/embracing the Magee endorsement--and any case, with the Dem nomination still up for grabs, it would seem to make sense for McCain to let others do the dirty work. More broadly, as Huckabee pointed out, the storm broke in March not October -- too late to derail the nomination, too early to do maximum damage in the general. (Okay, maybe not too late to derail the nomination. But if it proved potent enough for that, it would be fatal in the general. So the timing was optimal.)
If the release was planned, we might further assume that Obama had his great speech on race already in his pocket. I personally doubt this. I'm sure Obama wasn't lying about two days of sequestration getting the speech in shape. But given Obama's documented awareness that he wasn't done dealing with Wright, I'd also be surprised if the outlines and much of the guts of that speech hadn't been brewing in him for some time.