Forum Moderators: phranque
There's no fixed rule, if you think it's worth doing, do it, if you don't, don't. I do it both ways, but usually not, if SEO is a major concern I'd agree with vince, we've had pretty good luck with that, but we also have good luck without that.
If I had a really bloated topnav, that took a lot of HTML to generate, I'd be more likely to use that technique than if I didn't. On the other hand, if I want the navigation to appear high on the page for SEO reasons, it's better not to use that method, it totally depends on what you are doing.
Or you can mix and match, the navigation alone can appear top html, the header stuff bottom html, it doesn't really matter that much.
Search for 'source ordered html' and you'll find more reading on the question.