I'm Canadian, so I won't be voting in your elections, but if I was, you'd better believe I'd be voting Democrat.
Obama is the closest thing to a left-wing politician that the United States has had in decades, and as a dude who leans to the left, I think that is a good thing. His proposals on health care, the environment, and education all make more sense to me than the Republican alternatives. Furthermore, he's the only genuinely charismatic political leader to come along since I was born, in either the United States or Canada.
Furthermore, I'd ask the same question about McCain. Don't get me wrong; when I heard that McCain was likely going to be the name on the Republican ticket, I smiled. At the time, I felt that McCain represented all that the Republicans should be - he was the straight talker, a guy whose opinions were based on his experience, who did what he thought was right. Since then, however, I feel like he's realized that he's no spring chicken anymore, and that this is like as not going to be his last chance to be President, and as a result he's sold out to the worst, most petty and hateful elements of the Republican base. He used to be the straight talker, but I feel like he sold out, just so that he could have his dream of being President of the United States. Obama, on the other hand, is the same guy he always was - respectable.