In a very interesting interview, Eric Enge spoke with Matt Cutts on link building. What's good link building? In many cases, Matt thinks that the best links are those that are original research and provide value to readers in the form of a Firefox extension (that's somewhat related to the website). Matt also discourages against too much reciprocal links (but it's natural to have a bit). He also discusses affiliate programs, widget bait, SocialSpark (and says that they're doing a good job), and other link building topics.
It's an informative interview that deserves a full read. While some people believe it's common sense, many people have found that it's entirely valuable.
And original research really does pay off.
That little tidbit alone is one of the best, if not the best, way to get 'white hat' links. Combine it with an aggressive link building campaign to maximize your results, but the 'original research' concept of link building works like crazy.
I've found that the best articles include a lot of original research. It looks like I'm not alone.