The truth is that in the age of "modern journalism", you can't fully "trust" any major news outlet. CNN, FOX, MSNBC, network news - they all have their pros and cons and I would hesitate greatly before accepting any as being fully "truthy".
The key is to use them for what they are valuable for....some facts - admittedly mostly interspersed around gobs of opinion, spin, propaganda, and complex webs of deception. Toss in a healthy dose of sensationalism (which, by the way, makes for good blogging when applied properly) and it becomes a bit murkier to discern fact from truth.
A good litmus test is to carefully consider whether each piece of journalism that you take in is designed to steer you towards the one opinion or the other (usually that of the author/"journalist").
Example:
Objective journalism
Questions arose today as to what the high temperature really was? Some suburban residents reported high temperatures of 94 degrees, while thermometers in center city topped out at 92 degrees."
Sensational journalism
"A heated debate tonight in response to the questionable reports coming from the affluent suburbs of the city. Residents of Suburbia, a wealthy outer district of the city, reported a high temperature of 94 degrees. Local residents disagreed and were quick to point out that the center city thermometer only registered a mere 92 degrees, calling into question the credibility of the wealthy suburbanites."
Granted,I'm guilty of over-the-top sensationalism myself in those examples, but you get the picture.
:-)