I'm definitely Year of the Sheep = Hiro Sohma.

The little guy has attitude.
Fruits Basket was definitely the series during my middle school, pre-highschool years, and it's a great series to read and the characters are great. I'm personally not a huge fan of Tohru from the anime----as I find that her characterization doesn't change at all. But I do like her well enough in the manga.
My favorite character, however, is Kagura. It's weird, the majority of the fans despise her but I think if you look deeper inside her characterization, we'd understand her more.
ETA: I'm a friggin huge sucker for unrequited loves.