Most black people that do vote, will already vote for the Democrat candidate, regardless of who it is. How much of a boost from the black community could Obama get, if he would get 80% of the votes regardless of his skin color?
Clinton, on the other hand, could attain the typical Democrat votes (including the vast majority black vote), and also attract a lot of Independent, undecided or even Republican females. So I could definately see her getting more benefit out of her "handicap" than Obama, in regards to attracting votes that might go the other way, or even stay at home.
I don't see either as a handicap at all though, because the vast majority of people who would refuse to vote for a minority or female, would probably vote Republican anyways (you know it's true). So they probably won't lose even close to as many votes as they'll gain because of it.
As for which I'd prefer to win.. I'm still undecided. I liked McCain a few years ago, but it seems like he's gone downhill a lot. For the most part, none of them really inspire much confidence though. But after the past few years, I guess that's to be expected. But then, I've only casually followed thus far. We'll see how it shakes out down the road.