Is there a liberal bias in the media? I've thought about this a lot, and I like to think I'm pretty well informed about both politics and the media, and I listen to at least a few commentators on both sides of the political spectrum, so here's my opinion: No. There is not a liberal bias.
(And of course, I'm a college newspaper editor who proudly wears a "Republicans for Voldemort" t-shirt, so you know you can take my word for it, right?) :)
Seriously though, I don't think there is. Andrew Sullivan and lots of people like him cite a relatively recent study showing that something like 3 times as many reporters and journalists lean left as lean right. But what that study probably leaves out is the fact that just as many editors, publishers, owners, and advertisers lean right. (Roughly. Give me a break; I'm half-drunk at the moment, I won't have any statistics at all on hand.)
Some less statistical and more anecdotal evidence: the Burlington Free Press had a story about former president Bush's 80th birthday celebration. A front page story. And Vermont is one of the most left-wing states in the country. Does a front-page story about former president Bush's birthday sound like a leftist bias? And when Newsweek ran a story talking about of the people tortured at Abu Ghraib had nothing at all to do with terrorism, the story was the third in the issue, not mentioned at all on the front page. If the magazine had a liberal bias, why wasn't it a front page special report? In fact, let's look at the Campus Times again. there are only two people on its entire staff who I know are conservative and/or Republican (not that the two are the same, these days.) Who are they? the Editor in Chief and the Opinions Editor. That's even more pointless than the other anecdotal evidence, I admit, but still.
Some media outlets have a left-wing bias, sure. And some have a right-wing bias. (Fox News, I'm looking at you.) If you have a very careful measurement system you could probably determine if "The Media" as a whole has a political bias or not, but the difference would be so small and the margin of error so large that I don't think there would be any point. The only bias that exists across the board in the media is in favor of selling itself. That, in turn, means a bias in favor of sensationalism - whatever is going wrong, whether it's being done by a Republican president or a Democrat - and a bias in favor of the status quo - not offending anyone, not scaring off any advertisers.
On the other hand, maybe I'm only writing this to disguise the Communist agenda I'm secretly pushing as a news editor at the CT. Mu-hu-huhahahah!