One thing I think some people just don't get; black voters vote almost 100% democrat in all elections and it has nothing to do with the races of the candidates. There is no such think as undecided black voters. President Bush in 2000 got the highest percentage at about 10% if I recall, and that was shockingly high. Obama's race might effect enthusiasm among black voters but not the choice to vote democrat.
In the interest of a more accurate sample in determining if blacks supported Obama just because he's black, back that thang up to the DEMOCRATiC primary of 08. By the time things got hot and heavy it was a contest between Senator Obama and Senator Clinton. Obama got an overwhelming majority of black votes in the primary, right? No. Not exactly. Hillary Clinton initially was leading in the polls among black voters and had most of the black power players endorsements. Obama started to gain traction and was pretty much neck and neck with Clinton. If you look at JUST the black numbers, it was also essentially tied. Then Obama started to pull ahead slightly and like many politicians she and her campaign apparently panicked and started to deeply offended black voters. Specifically, she minimized the importance of and insulted the memory of Dr. Martin Luther King, Jr. Obama started getting compared to Dr. King due to his public speaking abilities. Sen. Clinton reacted by trying to compare herself to LBJ, saying MLK just made speeches but it was LBJ who got things done as a policy maker. This had the effect of sending the message to black voters that she didn't think MLK did anything of real importance and the roughly half of black voter support she enjoyed started to flock to Obama. This was not because of Obama's race but because of Sen. Clinton's insulting statements about Matin Luther King.