Well, on the sorta bad guy side, Mao from Disgaea 3. He's a crazy teenager who loves science and preforming experiments on things. If I met him, he'd wonder how I got into his home world and then probably drag me to his lab, seeing as how I'm a human girl.
On the good guy side, it's a tie between Yosuke from Persona 4 and Flandre from Touhou. Yosuke and I would get along well, because we are both city people who listen to music a lot, while Flandre and I...