This field is know as Christology. Two questions which are indelibly linked are: "Who was/is Jesus?" and "What was the significance of his death?" The answer to the second question determine one's "theory of atonement." Those concluding Jesus was and is the Son of God typically hold to one of two theories of atonement. First is the Ransom Theory (a.k.a. Christus Victor Theory). This theory states Jesus gave his life as ransom to pay for the sin of all humankind. Some believed the ransom was owed to Satan, others to God. I say "believed" because very few accept this theory today.
Second is the more widely accepted theory, the Penal Sustitutionary Theory. This theory says Jesus' vicarious suffering and death paid the penalty for the sin of humanity. Some believe all humanity, others only those humans who accept Jesus as Lord and Savior. According to this teaching the wrath of God against sin is "latent" in Creation. The penalty for sin is death--that is eternal separation from God. Jesus' blood, being of divine nature, is of infinite value. He paid the penalty for all sin for all time with his blood, making possible eternal union with God.
Those who do not accept the deity of Christ hold to the Exemplary Theory of atonement. Jesus was a good man who taught us to put others before ourselves, demonstrating his commitment to this way of life to the point of death. Jesus atoned in that we were ignorant of God's desires for us. He atoned for our ignorance by showing us the way we ought to live.