Fox is about as blatantly right wing as it's possible for a news network to get without going into violent reactionary territory. However, I take issue with the people who say CNN and MSNBC are just as far to the left. CNN is relatively neutral; their pundits argue whichever side they think will get them better ratings, and as a result their editorialism is fairly schizophrenic. MSNBC has liberal pundits on during the evenings, but unless something has changed since I last watched the morning pundits, they actually have a few conservative shows as well. Also, I don't remember Bill O'Reilly ever calling President Bush out for making a mistake; the columnists on MSNBC call Obama's mistakes all the time, even though most of them are personally liberal in their politics.
Also, OP, I'm pretty sure that Fox's byline is "Fair and Balanced," not "Fair and Rational." The best example of Fox keeping up the appearance of that name was on their show "Hannity and Colmes," which was hosted by one Republican and one Democrat, although they made sure the Democrat rarely got a good point in.