Shouldn't #navigation be inside #header?

Zen's "content first" approach means that we want to get the content of the page closest to the top of the HTML source output as possible. That means minimizing the amount of stuff in the header, even if we then use CSS tricks to put the navbar above the content of the page as it's rendered. Whether the "content first" strategy holds enough SEO value to offset this complication can be and has been debated, but it's unlikely that Zen will change at this point.