It was the episode "Throne for a Loss" that made me fall in love with her. She's a very capable woman - a strong woman, even though a captured warrior mistakes her as weak because of her compassion - because she tries to help him instead of assaulting him. Because she values him as an individual instead of perceiving him as an Other, as an enemy, someone to be scorned and forgotten.
But it's not just because of her goodness that she is strong - when he metaphorically spits in her face, she tells him, warns him, that she could rip him apart and that she would probably enjoy doing so - yet she does not.
And that is beautiful.
Another reason that I believe she is worthy of the list is because of her perception of the human body, of sexuality. She enjoys her body, she respects her body, and she is not afraid to express her beauty. When the prisoner in the aforementioned episode attempted to intimidate her by showing her his genitals, she was not fazed, but wondered if he had been taught to be ashamed of his nakedness, to treat it so. And then, as he had revealed his nakedness to her, she revealed hers to him.
It was very striking.
And of course, this sort of attitude had been threaded throughout the earlier episodes -- but it was in this episode that it was most strongly portrayed.
There was also the episode where they had the obligatory Don't Kill Aliens Just Because You Think They're Just Bugs -- bugs have personhoods too! And when Crichton was muses upon his new life and how to become accustomed to it she says:
Zhaan: Time and patience.
John: "Time and patience." Is that your answer for everything? [. . .] So who lives and dies in your world? Is it as arbitrary as it is in mine?
Zhaan: The answer is reverence for all living beings. Which may come with -
John: - time and patience.
And that is beautiful and it also reminds me of Vonnegut's philosophy, the one that people should love whoever is around to be loved. That's why I like Zhaan so much: she just sort of conceptualizes that.