I do not know enough to comment much. In the case of the C5, the changes from year to year were incremental. I suspect that the C6 is mostly the same way. The C6 drivers will be along soon to fill in the details.
'06 - differences:
different steering wheel - 3-spoke vice 4
XM antenna in the mirrors now rather than stuck on the roof or rear deck
Little "GM" badge on the rear fender right in front of the rear wheel opening