Well great I'm glad you're white thinking about voting for Obama. In fact its about time whites had an option to vote for a person not of their own skin color. Its about time blacks just had options. So we both, as black and white people, have a chance to exercise moving out of our comfort zone.
White guilt can get mentioned in these matters forever. There will never be a time when it can't I'd assume (no numbers to back it up) almost as much whites felt "guilty" 20 years ago as now, yet there was no evident representation of that in candidate support at the tiem. How come now its become a motivating factor? Maybe because his (apparent) credentials don't even make guilt a factor? Or, its some of the actual the "progress" like Deckard mentioned?