I have to agree with those who said "parenting" is the most rewarding job. I think it has the most unique set of challenges and as a result, has the most unique triumphs.
I am a teacher and a mother and I simply cannot fathom of feeling more triumphant in my influence of a student over what I will one day see my children become. Plus, every grandparent will tell you that grandchildren are the crowning glory of parenthood, and even more rewarding than children.
Along the same token, however, I think that many teachers experience the same rewards that parents experience when they truly love and care about a student and see that student succeed. I've had teachers in my life whom I considered "like parents" to me.