Those of us who grew up in countries where rigid identity politics (religion, caste, gender) is the norm, know that sometimes voters can indeed eschew prejudice in politics without revising broader cultural attitudes. Just because a male chauvinist votes for a female head of state or a casteist elects a candidate from a lower caste, doesn't mean the end of other personal predilections. Think Indira Gandhi and Benazir Bhutto and the status of the majority of women in India and Pakistan.Bigoted Indian voters could nevertheless vote for Indira Gandhi because she was Nehru's daughter. This is the difference between what you can tell of British attitudes towards women from Queen Elizabeth I becoming queen and Margaret Thatcher becoming prime minister. The regal association trumps all others -- just because the royal family practiced primogeniture did not mean that lower-ranking estates went to the first child: they still went to the first male heir. But Margaret Thatcher's election did show that Britons' attitudes towards women in positions of power had changed significantly.
Obama has no regal background to protect him from racists. So, if he is elected president, it'll be because Americans are looking past race to some extent.
But, only to some extent. I believe the comparison to royalty kind of explains why the negative attacks against Obama have failed so miserably. The USA is a republican country with no royal family: the cultural elite is all it has. Joe Sixpack may hate it, but he looks to it for social validation. McCain and Palin attacked Obama saying that he associated with "terrorists", but the proofs turned out be professors at Chicago and Columbia. And Obama, in his debates, came across as a reasonable, well spoken fellow with a measured way of talking. Not at all angry or sloppy. What the negative attacks served to do was to put him squarely in the elite. In other words, Obama was not like the poor blacks who a bigoted American thinks he sees every day; this Obama guy was on Tee-Vee and palled around with professors. He is part of the cultural elite, and that makes him acceptable.
P.S. This is also why the Rev. Jeremiah Wright videos were so damaging to Obama during the Democratic primary -- they bracketed him within a poor, angry, black milieu. This makes it interesting that even though McCain has a run a very bigoted campaign, only the Pennyslvania GOP has run ads of Rev. Wright. And indeed, those ads have coincided with a tightening of the polls in Pennsylvania.