Feel free to post angry comments but please make sure to read a few paragraphs first. What follows is by no stretch of the imagination a defense of Fox News; rather it is an appeal for more precise language when we discuss it.
In his recent paper on Fox news, Bruce Bartlett made an important distinction between ideological and partisan. These two concepts, while closely related, are quite different and yet people conflate them all the time and, as a result, most discussions of press bias don't make a lot of sense.
Political scientist Jonathan Bernstein: “It’s a real mistake to call Fox a conservative channel. It’s not. It’s a partisan channel…. To begin with, bluntly, Fox is part of the Republican Party. American political parties are made up of both formal organizations (such as the RNC) and informal networks. Fox News Channel, then, is properly understood as part of the expanded Republican Party.”
Ideologues support positions that align most closely with their belief system. Partisans support positions that they see as furthering the interest of their party. I'd argue that when we talk about "liberals" in the media we are almost always referring to ideological positions while when we refer to "conservatives" in the media we are generally referring to partisan positions. The Tea Party muddies the question somewhat but we're going to put that aside for the moment.
I realize there is a lot of gray area here, but, just as a thought experiment, try thinking about Fox News stories in relation to three continuous variables:
If you tune in regularly to Fox News, you will see a lots of stories with significant partisan and ideological components like marriage equality (which though a losing issue nationwide is still useful for energizing the base). You will also see a lot of stories like Benghazi with little apparent ideological components but with huge partisan ones. What you will very seldom see is a story in heavy rotation without a partisan component.
This Ideology vs, Partisanship distinction is particularly notable when a relatively conservative idea is adopted by a Democratic president and suddenly becomes unacceptable. In 2008, you could see cinservative pundits talking up Mitt Romney and listing his healthcare plan as a major selling point.
Coming from the Bible Belt (where Fox is enormously influential), there are a few other examples that strike me as particularly dramatic. Historically, there are few things that evangelicals hate more than Mormonism, Catholicism and the standard celebration of Christmas.
[Courtesy of Joe Bob Briggs]
From a partisan standpoint, there are huge advantages to building denominational unity and to using Santa and Rudolph to attack "political correctness," and that is consistently the approach Fox and conservative media in general have taken despite the ideological concerns of the audience. [There's another big story here about the way the center of power shifted in the conservative movement, but that's a tale for another campfire.]
It is easy to conflate ideology and partisanship -- they often overlap and there is a great deal of collinearity -- but confusing them can lead to bad analysis, particularly when discussing journalistic bias and balance.