Kira - Light --> the best ( evil, and very very smart ) ( btw Light is handsom to )
Ryuk --> almost the best, not very far ( funny and smart in a way )
L --> ( he is odd, mysterious and smart)
Mello --> the last of my favorite ( cool, mysterious and evil too )
Both L and Light are awesome characters, but I have to go with L for #1. Even though Light is really smart and ultimately beats L, Light was pretty much unmotivated until he found the Death Note, whereas L had apparently been using his amazing intellect to fight evil for some time. I think characters who don't even need special powers to do cool stuff can be even more awesome than those that do.
Without a dough it would be L I love him the way he sits, the way his eyes are, all the sweets, the way he looks at stuff, and just everything about him and I also love the way he holds stuff it is so cute.
Light because *fangirl mode* HE'S SO HANDSOME AND SMART AND IS VOICED BY MIYANO MAMORU!!! KYAAA~ *back to normal mode* but seriously, probably the main reason why I like Light the most is because I feel that he's the most complex character in the series. He's a metaphor of all the things one would do in a "what if" situation: What would you do if you had the Death Note? Would you want to create a perfect world? In the end, Light became the one thing that he was trying to dispose of. That is what fascinates me about him.