Favorites of Mine:
1. C.C. - Very much an interesting personality. I very started to take a liking to this character after the point where she loses her memory in R2, and in seeing how she acted around Lelouch.
2. Gilbert G.P. Guilford - He commands the Glaston Knights. He is extremely loyal to his princess. Very strong man of admirable character and chivalry. Not bad with a Knightmare either
3. Jeremiah Gottwald - Much for the same reasons as Guilford. And the Geass Canceller trick and being a cyborg are added awesome perks
4. Suzaku Kururugi - Despite the craziness that he has had to bear, he still maintains a reasonable amount of sanity. He is very strong, and has an enviable Knightmare: 9th Generation Lancelot Albion
5. Gino Weinberg - Though they made him look like a pansy at the end, for the majority of R2 he seemed to be a very cool guy. Serious when necessary, and just happy-go-lucky all the rest of the time. Regardless, he is an awesome pilot and The Knight of Three nonetheless.
Honorable Mention : Kallen Kouzuki, Shirley Fenette, Milly Ashford, Euphemia Li Brittania (why all girls? I dunno

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Hated by Me:
1. Nina Einstein - The dumbest genius ever. Not to mention a bit of a disgusting character. See episode 12 of Code Geass.
2. Lelouch v Britannia - Yeah, yeah he redeemed himself at the end. But I can't help thinking the world of Code Geass might have been a better place if he never existed. Too many of his actions lead to fatal consequences. He killed Euphy, he cannot be forgiven.
3. Rolo Lamperouge - yeah he also redeemed himself, but nonetheless, he is too self-centered. And he killed Shirly, so he cannot be forgiven either.
4. Charles Zi Britannia - Very much an idiot. Need I explain? V.V. ties with him though
5. Clovis la Britannia - The pansy who dies in episode 2, yet keeps on being mentioned repeatedly throughout the series.