Those on the left of the party don't support her because she is the most conservative Democrat still in the race. I've no idea why the right dislikes her so vehemently. Ultimately her husband's greatest successes in office came from co-opting Republican ideas.
That said, I'm kind of amazed at the willingness of various commentators, male or female, to make blatantly sexist comments about Hillary. A female McCain supporter felt free to call her a Bitch on camera, and Mike Allen of the Politico commented "What voter in general hasn't thought that?" Chris Matthews has referred to her as "Nurse Ratched" and to her male supporters as eunuchs and castratos.
I don't expect that the folks in New Hampshire following her around with "Iron My Shirt" signs were supporters of any of the major Democratic candidates. Try to imagine signs with a roughly equivalent insult directed at Obama or Bill Richardson, and then imagine photos of the incident showing up on the front page of national newspapers, or TV commentators giggling and joking over a videotape of the incident.
OK, I got that off my chest. Women I would support for president if they were running:
1. Barbara Boxer
2. Christine Gregoire
3. Janet Napolitano
4. Hillary (as I said, not my first choice among present candidates but at least she hasn't suggested staying in Iraq for hundreds or thousands of years).