I don't think Hillary will win... for a number of reasons.
First, she is an amazingly polarizing figure. Love her or hate her... there isn't much middle ground. Of all the candidates expected to run on either side (with the possible exception of Newt Gingrich) she enters with the greatest percentage of voters already saying yes/no. She will have a hard time changing any opinions of herself and has a huge uphill battle to swing any voters to her side that aren't already there.
Second, she has a lot of skeletons in her closet from her "husband's" term in office. If you thought the Swift Boat Vets were digging up some questionable stuff on Kerry, wait till you see what comes out when Hill decides to run for prez. The right will have had 8 years to fully flesh out the scandals she and Bill managed to side-step when he was in office. (And yes, his actions will reflect on her) She'll be more prepared for it than Kerry was but it will be every bit as damaging if not more.
Third, have you ever heard her give a speech? She gives a droning monotone that escalates in volume until it's so shrill it hurts. At that point it doesn't matter what she's saying, nobody wants to hear it. Sad to say it but the race for prez is as much a popularity contest as anything... and she doesn't have what Bill had. There is nothing particularly endearing about her.
Fourth, it would be a mistake to think that anyone is just going to hand the nomination to her. The Dems made that mistake with Kerry last time around. They might be a little skittish about doing it this time around. There is a whole cast of characters in the Democratic party who will be formidable opponents. They have more experience, less controversy and are just plain more likeable than Hill.
The few things she does have going for her are substantial though. Let's face it... there are a lot of women who will vote for her JUST because she's a woman. It may sound superficial to say it but you're kidding yourself if you discount that fact. Combine that with the narrow margin between left/right in this country and there is more than just a little bit of potential for her to pull it off. Another thing she has is the ability to raise money by the truckload. Her candidacy will not be hurting for millionaire donors.
Ultimately it will come down to who the Republican candidate is. Rudy could beat her. The big question with him is if the Republicans will vote for a pro-choice guy. There are a couple of other possibilities out there as well.
Either way, I predict that this will be the NASTIEST presidential campaign we've seen in our lifetimes. Don't forget your helmet.