Everyone else - is there a Wikipedia policy on balance in external links?
I don't think there's one written; my own perference would be that on a page covering a general subject, external links should either point to reasonably balanced articles, or else have a balanced number of links to articles from different points of view. On articles specifically about a certain point of view, one would expect links to biased articles to be the norm, though a rebuttal article or two wouldn't be out of place either.