My favorite character is Neku, probably because I'm a lot like him. (Although I like/get people a little more than he does) Joshua is second favorite, although I was really mad at him for killing me when I found out the first time, then felt a little bad when it really wasn't him, then mad again when it really was him, but that time it was better because at least I knew why. Great plot. But even when I was mad I had to respect his mysterious/secretive nature. He's pretty cool.
Kariya was my favorite Reaper. Minamimoto was cool, but I was annoyed with his math speak because, at the moment, I am failing math and I really didn't want to think about it. (I used to be really good at math, believe it or not.)