I think Fox has an obligation to look at what others are reporting and deliberately go out of its way to ask, "Should we be covering other stories? Other angles? Is this really news?" The answers are often surprising.
For ex., say for a moment that the Bush/TANG story was in fact true. What real difference would it have made? In "normal" circumstances, an objective and honest news network wouldn't have given that more than a throwaway line in some weekday newscast, and that would have been it. My point is, since bias is in part shaped by story SELECTION---not just "framing" stories or "slanting" them after they are selected---then Fox has to be vigilant to select "fair and balanced stories."
This shows up most recently in Iraq, where we ONLY hear (even from Fox, often) about the latest bomb, but not the 99% of the cities that are calm, where power is on, where people are going to school and work, and where the tiny seeds of liberty and democracy are taking root.
You are right that slanting can come from what you choose to cover, but HOW you cover the story is more important.
I remember reading the memos the Outfoxed people released, and was rather impressed about how Moody tells the staff to look for angles that get underplayed etc.
Yet, still being fair and balanced.
Objectivity is impossible, but you can be fair and balanced, and I think Fox has that.