I agree with arctic a bit here. A good % of people who used to listen to Howard Stern on NBC (or any other station he's ever been on) hated him but they wanted to hear what he would say next. Bill O'Reilly evokes emotion from an audience, whether the audience worships the words coming out of his mouth or think he is the root of all evil. The connection, regardless of it's polarity, is what keeps people watching. Many of Fox's audience is inundated with their style: ridiculously fear based, misogynistic, campy, racist, and hearkens back to print sensationalism. It may be all they watch and unfortunately they are too scared or unintelligent to understand the difference.
Bias in the media comes from all angles though. The late Tim Russert was regarded as one of the greats because you didn't truly know what 'side' or viewpoint he favored, he reported and seemed like he tried to get to the root of things and left his sided opinions at the door.
I'm an American. I occasionally watch CNN, Fox, and MSNBC for basic sh** and read The Economist (brilliant), The New York Times, The Star Ledger (NJ) and The Guardian UK. I never take anything I see or read at face value though. You have to internally audit any source and form your own opinion with regard to its bias or veracity.