I voted for pretty much everyone. Light is my favourite Death Note character in the entire series, for being an evil phsychopath with a God complex (But that's just the fangirl in me), but managing to remain a realistic character; he is brilliant yet in some ways stupid, stupid enough to think that it's possible to make the world into a perfect place. His flaws are all realistic despite having impossible intellegence (But that's another thing I love about him), and he makes human mistakes.
Misa and L are my two second favourite Death Note characters, Misa for being fascinating and tragic, and having such strong emotions, and in general, she has amazing emotional strenght for being able to live the things she goes through and managing to remain that purity and cheerfulness of hers. She's crazy as well, but not phsychopathic, she's smart in some ways and stupid in others, but not freakishly brilliant like most characters, and she is just amazingly strong- most characters, had they gone through what she had, would have become very angsty characters, but she didn't. And then there is her undying love and devotion for Light, which is an intriguing part of her as well.
I also believe that Misa is rather smart but doesn't show it; you cannot be stupid and a good actress, but I think that acting is the area where Misa is most intellgent, and 'dumbs herself down', for the lack of a better description, on purpose, because it sells easier and is how she messes with people's minds- I think she didn't show her true intellegence near Light on purpose to mess with his mind and earn his trust, which worked.
I admit, I never liked L all that much in the beggining, but he started to appeal to me as the series proggressed- I love how flawed he is, how he is an odd person to represent the 'good guys'; he, I think, is smart in many, many ways, smart enough to understand that you cannot make the world perfect, and basiaclly 'white' when compared to Light, yet he is not above torture and killing people to reach his goals. He represents that there aren't actual "Good" and "Bad" people in Death Note, that everyone are 'Gray'.
Almost everyone come third; I loved Matsuda most after chapter 74-76, don't remember exactly which, where he questions if Kira really is evil or not, and especially after when he
Mello, Near, Mikami are all awesome, and I love Sachiko as well; she, too, is a strong character for living through experiences that must be veru painful for her, and I also love all the girls in the series.