Why did Jesus have to die?

1st Peter 3:18 tells us that Jesus "never sinned, but he died for sinners to bring you safely home to God."  (NLT).  From the time of Anselm of Canterbury, circa 1100 A.D., who offered his "satisfaction theory of atonement", we have seen Jesus as having died physically so that we could live spiritually.  But what does this mean to us today, as modern believers?  Perhaps for us, it is Jesus' example that is so meaningful: he was willing to suffer, to give in the ultimate fashion, as a sign of his love for humanity.  What are we willing to do for each other?  For our faith?