Since there's a huge war on paid links, is it true that you should avoid link buying at all costs? That means even using sites like press-release distributor service PRWeb.
Perhaps -- but PRWeb's goals are obviously not in the link building sphere. The goal for PRWeb is promotion of a particular service or website, not for link building. It's uncertain how Google handles links that are generated through PRWeb.
Randy says an important piece of advice for how you should handle this in general:
Truth be known, all link building should be approached from a Promotions/Advertising/Marketing mindset, not an SEO one. Get links that will stand a chance of bringing you real traffic from real qualified people visiting your site.
Forum discussion continues at High Rankings Forum.
Update by Barry: See an older thread on this topic at Search Engine Roundtable Forums where Matt Cutts basically said links from PRweb releases no good.