As you know, I'm Catholic. This means I'm ultra family-oriented (and they wonder why Republicans are winning the Catholic vote these days)! Now I'm not trying to say that Protestants aren't family-oriented - in fact, the best Protestants I know are all about the family. Moreover, not only do both Catholics and Protestants maintain that human families are important and central, but we also both agree that God himself is a family of divine Persons (Father, Son, and Holy Spirit).
Where I differ from Protestants is regarding the familial relationship between the human family and the divine family.
Martin Luther, and Protestants after him, developed a view of salvation which compared it to a legal courtroom. This courtroom each human is on trial for sin. By having faith, however, God sees the righteousness of Jesus covering the sinner and his sins. In a sense, faith acts like a shield that blocks one's sinfulness from God so that God can only see holiness - even though it's not really the holiness of the sinner.
Now I'm in now way trying to say that there will be no judgment of the sinner after death. But I believe a courtroom legal proceeding misses the point of God's plan. The Father sent the Son in order to bring the human race into a family! This human family, however, is not a family disconnected from God but intimately united to him through his Son, Jesus Christ. Moreover, it's no longer a question of "me" and Jesus but rather "we" and Jesus - for only in Jesus can we find personal salvation and true communion.
Can you see now what I'm getting at when I say that the Church is a family?
What I believe is even more important, however, is that God doesn't simply declare us to be righteous (i.e. the judge declaring the accused innocent) but actually makes us his sons and daughters. St. Athanasius said in the 4th century that: "The Son of God became the Son of Man so that the sons of men could become the sons of God." At our baptism God actually recreated us as his children, infusing into our souls a created share of his own divine nature (grace).
(I'll add some biblical quotes on this for you later!)
What I'm getting at here is that, by the fact that we who are in Christ are the children of God, we are holy not by being covered with Jesus' holiness but by being cleansed from sin in our very souls. In actuality, we really become holy! As sons and daughters of the Father, God teaches us and raises us in holiness. He gives us the grace to merit our holiness (though the initial grace he gave us was of his own free will and could never have been merited by us).
This view of the children of God is not often thought about these days! In the end I can't think of anything more joyful or more Fatherly than the thought that by being in Christ we truly are the children of God!