I picked L, I think I don't need to explain why, he's L
and Ryuk, he really was the winner in all this
I also liked Naomi Misora, to me she was the only clever female in the show (Misa was funny at the start but then...) and it was a shame that "she was able to uncover crucial plot information "faster than...thought" " and had to kill her soon.
I wish they make an OVA of the BB Case basically because the main characters are my favourite ones and the story was interesting (in the end I liked BB too)