Which Comes First? The SEO or the Egg?

It's so easy to forget that for an industry that's been around over a decade, there remain new search engine marketers trying to learn the fundamentals. And, ten years later, there's still no consensus on exactly what those are.

A thread at Cre8asiteforums called Starting The Seo Process: What are the bases you cover to get the site on a good SEO path? illustrates the problem.

What comes first? Strategy or tactics? Business plan or keyword research? Do you create for people or Google? Links? Dynamic content? Customer research?

You get the idea.