Keep in mind that any agency, no matter how even-handed and unbiased, will inevitably receive criticisms of bias from someone. If you're ultra-conservative, you'll see neutral reporting as liberal; if you're ultra-liberal, you'll see neutral reporting as conservative. This is simply a result of not seeing your own agenda, and thus interpreting that agency as skewing in the opposite direction. For every person who says CNN is part of the liberal media, I've seen an equal number saying it skews conservative.

This isn't to say that plenty of sources are not, indeed, biased, only that "all news is biased" has become a generic truism. In the CNN example, the problem is more a matter of shoddy journalism that's aimed at sensation and reductive explanations than a specific bias in one direction or the other. You seem to presume that the problem of corporate news is a political agenda, but while an organization like Fox News may stand out, the truth is that most corporately owned news organization are problematic not because of such top-down agendas but rather because of the need for profit, which encourages sensationalism and reductiveness, regardless of which way a story might lean (which is why everyone thinks CNN offers the opposite of their own political leaning -- they take the stories they agree with for granted, and focus on the ones they disagree with as examples of the problem; the truth is that CNN is all over the place in terms of politics). And as the internet has made newspapers more obsolete and taken viewers away from advertiser-funded TV news, this need to run sensational, attention-grabbing stories has become all the more significant.

Personally, I favor nonprofit organizations like NPR and public service broadcasters like the BBC, as they provide more in-depth features that presume their audience is intelligent, rather than overly reductive blurb-style coverage. Like any other organization, they do need to retain an audience to maintain funding, however they're at least not profit-driven in the same manner as corporately-owned news sources.

But honestly, I recommend aggregators like Google News: if you want a fair sense of the news, scan multiple sources and you can quickly get a sense for who seems to be providing better or worse coverage or a particular story. In many cases, news sources may be very good in one area and very poor in another (good political coverage but horrendous science coverage, for example), or may cover one story very well simply because they have a good reporter assigned to it.