I like Jeremiah because he is the most loyal soldier Lelouch has. He's also a cyborg with a GEASS CANCELER. He was also pretty cool when he beat Anya. He's a great Knightmare pilot.
My fave is rolo. How can you not have rolo!? D: My second favourites are schneizal, just cause his ideals are pretty cool even though he gets a bit corrupt and jerimiah although schneizal just wins. But you gotta admit... ORANGE-KUN!!!
My favorite is Euphimia because she was so sweet. Also she had the right idea on how to bring some type of peace to Area 11 before Lelouch used geass on her. She treats everyone with respect even if they aren't Britannian. Another reason is that she knows Lelouch is Zero, yet she doesn't tell anyone.
for me its either Lelouch or Lloyd :D Lelouch is an obvious one he's intelligent and thinks more down to earth in battles than most and Lloyd... i don't know.... i like his weirdness and his voice and also how much he doesn't care about the opposite sex ^-^