I have no idea how Obama would be regarded if he were white. (He might be regarded as this generation's Jack Kennedy; the two have a similar quickness, youth, charisma, and capacity for humor.) But for any successful politician, there are many necessary conditions for their success. Would George W. Bush be president if his last name were not Bush? Would Al Gore have become vice-president if his last name had not been Gore? Would Senator McCain be a serious candidate for the presidency if he had not been held prisoner in Vietnam? Would Bush, Gore, or McCain be where they are today if they were African-American or Hispanic? (What kinds of questions are these?)
Of course, as I've noted, the experience issue should not be solely thrown at Obama. Indeed, if I recall correctly, of the major players in the '08 race, Obama has more elected experience than all the other top candidates save John McCain (comparing to Romney, Giuliani, Edwards, and Clinton). Indeed, if you want to talk about a candidate who we should be hitting on experience grounds, how about Rudy Giuliani, whose electoral experience is two terms as mayor. Yes, I know New York City is really big, but still--I don't think one can credibly say that Obama doesn't have enough national experience to become President when you're seriously considering a candidate whose never even risen to the level of state government.
Meanwhile, in this list of early '08 endorsements, I noticed that Obama had picked up the support of Illinois Democratic Representative Bobby Rush. Rush, of course, faced a primary challenge from Obama in 2000, which he beat back by labeling Obama "not Black enough" for the district. I would have thought there would still be some bad blood from that. But it's all for the best--it would be highly embarrassing if Obama had a defector from his home congressional delegation.