I was positive bambi couldn't win the election because he needed the votes of many people who voted for Bush in 04. Well, he got them, and now I am slowly learning who these types are. They disliked Kerry, not because he was a leftist but because he was a dork. They liked bambi, despite the fact that he is a leftist, because they think of him as cool. This truly was an American idol election. What a bunch of complete idiots.
I think there is some portion of the electorate that does just form some general impression of the candidates, and then casts their votes based on how they feel about them. One of the first televised pieces of evidence for this is some old b&w footage with several women saying: "Kennedy is so good looking," and they planned to vote for him.
Obama got a big white guilt vote this year, people who just felt good voting for a black guy.