As Jesus is the cornerstone upon which the Church is built, so are his teachings the unifying cornerstone of Christian doctrine.
Empty Cross Syndrome
Protestants do not often display a cross with Jesus on it. That is more of a Catholic thing. I have even heard Protestants criticize Catholics for it as focusing too much on Good Friday and not enough on Resurrection Sunday, but I can find no biblical reasons for such condemnation. It is just a matter of choice. Perhaps we Protestants are too squeamish. Perhaps the Passion of the Christ (movie) could only have been made so well by someone associated with Catholic tradition. Yet we Protestants do remember the passion of Christ in the bread and the wine, but perhaps we are also somewhat like Peter in wanting to avoid the fact that Christ had to suffer (Matthew 16:21-28). A healthy focus on the cross is a reminder that we too must take up our crosses and follow him.