I would have to go with Izaya from Durarara! He's not exactly the good guy, but I can't consider him a bad guy either. He is a major asshole at times but I still 사랑 him. Especially when he stomps on unsuspecting high school girls' phones while laughing like a maniac. I have to admit that I laughed like a manic too while watching that scene.
Well, it's probably because he played an evil guy for 300+ episodes, but in the end, he was good xD He's something 더 많이 like a tragic hero (SPOILER cuz he died T_T), but I think 당신 can consider him and anti-hero, too xD 당신 know, playing a villian and doing some bad things, but being actually a good guy xD Anyway, I 사랑 your choice
Um, I'm not sure if he's my number one (too tired to think xD), but I'll go with Lelouch from Code Geass this time xD He's a perfect example for an anti-hero, at least I think so xD