Why does Jesus speak of himself in the third person? There are a number of places where Jesus refers to himself in the third person.  The most common is when he uses the title 'Son of Man' (by my count, there are some 78 times Jesus uses that title in the gospels!).  For example Matthew 16:13 (NIV):


  When Jesus came to the region of Caesarea Philippi, he asked his
  disciples, "Who do people say the Son of Man is?"


I understand the significance of that title (e.g. Daniel 7:13-14) but why does Jesus use it so often to describe himself?  Complicating matters in my mind is the fact that the various gospels seem to use 'Son of Man' and 'I' interchangably.  For example, Mark 8:27 is a parallel passage to the one above but it says:


  Jesus and his disciples went on to the villages around Caesarea
  Philippi. On the way he asked them, "Who do people say I am?"


One other major case of third person titles that intrigues me is in John 17 where Jesus is praying and refers to himself as God's son and 'Jesus Christ':


  1After Jesus said this, he looked toward heaven and prayed:
  
  &nbsp; "Father, the hour has come. Glorify your Son, that your Son may
  glorify you. 2For you granted him authority over all people that he
  might give eternal life to all those you have given him. 3Now this is
  eternal life: that they know you, the only true God, and Jesus Christ,
  whom you have sent. 4I have brought you glory on earth by finishing
  the work you gave me to do. 5And now, Father, glorify me in your
  presence with the glory I had with you before the world began."


Why does he suddenly refer to himself as Jesus Christ here but nowhere else?
I think a large part of His reason for doing this is to make shed more light on His identity. The title used reflects additional information about the person using it. So, to look at a few of Jesus's many titles:


"son of man" -> associates Jesus with the glorious figure seen in Daniel 7  
"son of David" -> associates Jesus with the promise God made to David about a descendant who would sit on the throne forever  
"son of God" -> describes Jesus as a king (since some of the kings of Israel were called "sons of God") although it is sometimes used in other ways by other people ("Son of the living God", "the Son of God") to refer to Jesus's divine nature.  
"messiah" / "Christ" -> associates Jesus with prophecies about a prophet from God who would rescue Israel  


So when Jesus used a particular title, it would evoke a particular image and bring to mind different ideas, even though they were all correct.

Short example of how this makes a difference. Say I'm trying to get into a fancy restaurant and the guy at the front is looking doubtful that I "fit in". I could say (assuming it was true):


I'm Richard, let me in.  
I'm the son of the owner of this restaurant, let me in.  
I'm cousin to the President, let me in.


They might all be true, but I'd be gaining something from the use of different titles.

Likewise, Jesus used different titles to show different aspects of Himself. Here is a great article on some of them (although it does miss a bit theologically).