Is there bias in the media? Did you just inhale and exhale? Have you swallowed any saliva today? Of COURSE it's biased. We're human beings, and by nature we're not completely objective. However, it doesn't seem like any news source is even striving for objectivity any more. They all seem to want to oversimplify issues into an either/or scenario. How dare anyone have a nuanced view on abortion or welfare or foreign relations?
There's also, as others have pointed out, a bias toward ratings. People will tune in to see a house fire, a car accident or a plane crash, because those stories are exciting, whereas nobody wants to watch that snooze fest of a city council meeting where people are making laws that could affect you personally for decades to come. That's boring!
If we read the long and thoughtful articles in major newspapers and magazines, maybe we would see how complex some issues are and maybe television networks would present more complex stories to win their audience back, and maybe delve into the possibility that there is more than one (or two) ways to look at a given issue. In some ways, we get the news media we deserve.