Which person represents Christ?
The obvious choice is the Samaritan - he is the one who cares, he is the one who heals. And given the feelings that the Hebrew people felt towards the Samaritans, it could be also said that Christ descended below all things - including the social class of people felt to be inferior.
Here is one other observation:
Could Jesus also be the man who was the victim of the attack in this parable?
Remember, a priest and a Levite both passed by (the preachers of their faith) the victim and walked off, leaving him to die. These are people who profess to know God intimately, but pass by the Son of God without recognizing Him.
Instead, he was rescued by a man who didn't know who he was or what he represented, but cared anyway.
Which person in this story would we be? How many times are we that priest or Levite and walk off, leaving someone in distress? How many times are we the Samaritan?