It was years ago when I worked at it seriously, back then I didn't think nofollow mattered. I think the objective measure of the value of a link is how much traffic you get over it as you can't directly measure Google's PageRank [1]
I think you want every kind of link you can possibly get in large numbers. That includes mentions in blogs, social media, directories, Wikipedia (if you can't add your links to Wikipedia you can always take out your competitor's links and leave a comment that says they are spam... deletionists will love you!) both high quality and low quality, human curated, automatically generated, etc. White hat and black hat SEO go together like peanut butter and jelly.
Don't forget that you want keywords that you want to rank for in the anchor text because one of Google's innovations was indexing the anchor text.
Site architecture matters more than you might think. Most of all it is easier to rank for longer and more obscure query terms than it is to rank for shorter and more popular ones. A corollary to this is that you want to have many pages on your site about many topics because each one is like buying a lottery ticket. For that matter, it is a lot easier to build links to a site with 20,000 pages than a business card site with 5 because a given source might link the business card once but might drop 2,000 links to the big site.
[1] In the original PageRank paper, PageRank transmitted over a link is proportional to the traffic estimated to go over the link assuming web browsing is a certain Markov process