ADDED: The consensus on the Television Without Pity discussion board is that Amanda lost it at the final tribal counsel. There's some interesting gender critique:
[Orion7} I think she lost because she didn't step up and take responsibility. She needed to say, "Yes, I lied, and it bothered me to hurt people's feelings, but I wouldn't change a thing, because it's what got me here." Instead, she hemmed and hawed and looked timid. She looked as if she rode in on Todd's coattails, instead of the other way around. Todd admitted that he'd lied, and that it was strategic, not personal....She continued her niceness routine, which worked to avoid elimination, into the final council where she needed to claim credit. She thought she could win by being likable. It's funny to read the TWoP discussion and see how many people were disgusted by her "doe eyes." Is this anything like real life? Does it say anything about the glass ceiling? Perhaps not. In real life, you don't have to win favor specifically from a group of people you've harmed and with whom you have no ongoing relationship.
[Miss Alli] Colby and Tina notwithstanding, when men and women from the same alliance face each other before a jury, the jury generally says, "He was a spirited, awesome imp; you were a backstabbing phony." At final tribal councils, boys rule and girls drool. So it was and ever shall be.