He has several positions that make him very popular. First off, foreign policy wise, he advocates immediate withdrawal from Iraq, and has opposed the war from the beginning. He thinks that the federal government has overstepped its powers in the war on terrorism, and promises to restore many civil liberties that have been infringed upon. He also wants to eliminate the IRS, scaling back many government services and programs to make this possible. In congress, he votes against any bill that increases federal spending or that he believes to not be in congress' authority to pass according to his strict reading of the constitution (garnering him the nickname Dr. No).
As you might be able to tell, I like some of those policies, mainly his stance on civil liberties, and even considered myself a supporter of his at one point. But as others noted, he simply supports too many other things that would be disastrous, like a return to the gold standard, extreme isolationism and cutting off so many social services.
@God.: I haven't seen any evidence that he is racist. There was one incident that a person working on his campaign printed a racist pamphlet in his name, but he disowned it once it came to his attention. Care to inform me how he is racist?
@Misty: I haven't done enough research on the election yet, but I like Obama the most so far. I'm curious why you seem to support him, it may help inform my own opinion.