It's been a tough year for Channel 4. Ofcom's report on Celebrity Big Brother, the phone scandal on Richard and Judy, controversy over The Great Global Warming Swindle and Diana: The Witnesses in the Tunnel as well as profits plummeting 70% in 2006 as a belt-tightening chancellor moves into No.10. 25 years after launch, we present cases for the prosecution and the defence as we ask the question - has Channel 4 lost its way?