1 Rigged GM truck explosion
2 Altered Video to hide the fact that it was a black tea partier was carrying an weapon at a town hall meeting, while the anchor implied white violence was imminent.
3 Zimmerman tape selective editing
4 Romney tape
Need to add:
5 The slandering of Richard Jewell during the 1996 Atlanta Olympics. He was the security guard who found a bomb. NBC blamed him for setting the bomb.