I would not buy links from people who sell them on webmaster or marketing forums, but there is one particular forum I can think of which discusses some areas I discuss on my blog, and how to get those people who frequent that forum and have blogs to link to me is one of the solutions I have to getting myself out of a minor hole. Reason being: A few people who have sites similar to mine did link to me voluntarily and it has created a big boost in both, my rankings and my direct traffic.
This sounds like unreasonable fearmongering to me. Buying links is good. If the links generate you the right type of traffic. And if you know where to buy, Google shouldnt be of too much worry. Google comes, Google goes, but the right links will provide the right traffic for many years to come.