Was removing one's shoes a special sign of respect? In Exodus 3:5 KJV God tells Moses to remove his shoes:


  And he said, Draw not nigh hither: put off thy shoes from off thy feet, for the place whereon thou standest is holy ground. 


There is no doubt that God deserves and should be given every respect we can offer.

I can find no information as to why Moses was to remove his shoes at the burning bush, other than as a form of respect.

While I understand that the ground was Holy because of the presence of God, I have wondered if removing our shoes in the presence of God shows a higher form of respect.
Regarding the importance of shoes:

Taking off your shoe and giving it to someone was a sign of redeeming and changing in the ancient world.  

You can find more in 

Ruth 4:7 KJV


  Now this was the manner in former time in Israel concerning redeeming
  and concerning changing, for to confirm all things; a man plucked off
  his shoe, and gave it to his neighbour: and this was a testimony in
  Israel.


Regarding being barefoot:

Being barefoot actually had a lot of different meaning in ancient times.

As a sign of mourning:

2 Samuel 15:30 KJV


  And David went up by the ascent of mount Olivet, and wept as he went
  up , and had his head covered, and he went barefoot: and all the
  people that was with him covered every man his head, and they went up,
  weeping as they went up .


As a sign of humility:

Isaiah 20 KJV


  In the year that Tartan came unto Ashdod, (when Sargon the king of
  Assyria sent him,) and fought against Ashdod, and took it; At the same time spake the Lord by Isaiah the son of Amoz, saying, Go
  and loose the sackcloth from off thy loins, and put off thy shoe from
  thy foot. And he did so, walking naked and barefoot.And the Lord said,
  Like as my servant Isaiah hath walked naked and barefoot three years
  for a sign and wonder upon Egypt and upon Ethiopia; So shall the king
  of Assyria lead away the Egyptians prisoners, and the Ethiopians
  captives, young and old, naked and barefoot, even with their buttocks
  uncovered, to the shame of Egypt.  And they shall be afraid and
  ashamed of Ethiopia their expectation, and of Egypt their glory.  And
  the inhabitant of this isle shall say in that day, Behold, such is our
  expectation, whither we flee for help to be delivered from the king of
  Assyria: and how shall we escape?


Please consider reading this regarding The Role of the Shoe in the Bible.