Tie between Kyo and Yuki.
They both are the ultimate duo. Yuki gets to kick Kyo in the face, and Kyo get's to do all this 'learning' about life and being around others.
Hiro, when he's all annoying and a little *asterd to Tohru. Then he gets to be cool later on.
As for who Tohru will end up with..
I know by the mouths of those who would spoil and wont spoil it here.