Reporters vs. Sophists
The biggest distinction for me between a magazine like the Weekly Standard and The Nation is not so much any ideological difference as a fundamentally different approach to journalism. The Nation will have, in any given issue, a good number of reported articles -- where the author went out into the world to find unreported facts (with no doubt, some commentary too), whereas the Weekly Standard will have nothing but sheet after sheet of commentary, backed up by a few Lexis-Nexis checks.
The right wingers barely know how to do journalism; they hardly ever show evidence of it anyway (take a look at National Review -- where's the reporting?). Or perhaps it is that they view it that the major newspapers and magazines are doing the leg work for them, and that it's their right to feed like vampires off the work. Because that's what's going on.
In any case, when these two approaches to journalism are brought together in the same arena, like PBS, it doesn't produce anything close to 'balance' -- PBS czar Ken Tomlinson's rule of thumb. Put Frontline or Now head to head with that Wall Street Journal show, and the seesaw tilts heavily in favor of the ones who explain to viewers the facts behind the story.