He is hands down my favorite character of all time. It's not even a contest.
"Zoro is a man who lives his life following a strict personal philosophy centered around justice, honor and heroism. He strongly believes that saving a life is a debt that must be repaid by those with virtue, and that repaying this debt is the way of a true swordsman. To this end, Zoro would follow the request of someone he owed almost blindly, even when it contradicted his other beliefs."
He is pretty much a role model and someone that I deeply respect.