You may not have understood what I wrote before. What you're talking about is selection and gatekeeping bias, something that scientific studies always measure when analyzing the media. If you only report on stories that make Obama look good while ignoring all the ones that make him look bad, your reporting is biased even if your coverage of the stories is 100% unbiased.
So if Fox News is 80% conservative opinion programming I consider that a biased source, but not a biased NEWS source unless their news coverage is also biased. (which it is). If your argument is that the rest of the media is so heavily populated by liberal opinion programming that has a liberal slant to it...well... I just can't possibly see how that's accurate as opinion programming has more conservative voices to it than liberal ones. As far as news coverage goes, which is what I thought we were discussing, there simply is not substantial aggregate media bias.
Forgive me for pushing this but what do you consider opinion programming? National talk radio (Sirius XM) has 3 Political channels that are strictly for political talk radio. Sirius Left, Patriot and POTUS. They also have CNN, Fox News, MSNBC, BBC, and NPR. The National News stations are obvious and so are Patriot and Sirius Left. POTUS has about 50/50 and their coverage of the election was spot on.
Do you have any sources that show national viewers/listeners and the times? There are only 24 hours in a day and based on what is national news (cable or talk) I can't possibly see how your statement makes any sense unless you are using local talk as a reference which is irrelevant given their audience size.
You mention that it is gatekeeping and selection bias, if you know what type of bias I am talking about how can you possibly look at Fox or MSNBC and tell me that they do not have bias? The Bengahzi/Fast and Furious/Solendra vs Pro Gun control/Abortion Doctor NonCoverage/Treyvon Martin should be clear examples of this.