I think that most people here might know who my favorite is based on my profile pic, and in the other anime/manga character thread, I spelled out these reasons:
"She's beautiful, smart, is a fighter, stands for fidelity, excellent example of a female leader and doesn't sink down to stereotypical male leadership examples. Is the polar opposite of her boyfriend Agito though she assist him in anyway she can. She's also kind and compassionate, sort of again the polar opposite of Agito. I also like Mizuki and Natsuki, but Shizu is my favorite of the women from Guyver."