When you assign a priority to URLs with Google sitemap, do you give the higher priority to your actual content pages (articles, etc) or to your sitemaps / navigation pages, which contain links to all of the articles?

IMO you should give higher priority to your content pages, they are important for Google and about sitemap page; it is going to be crawled by Google.

Tough call. The content pages are the "bread and butter" but the portal type pages are more likely to rank well naturally. I never really gave it much thought because Google does not seem to give any weight to that field (at least not yet anyway).

I would give it to the content pages to make sure they get looked at first. I agree with stymiee though that they don't give much weight to it.

Almost two months ago, I submitted a Google sitemap where I gave the forum display pages more weight than the thread pages. I was hoping that this would get Google to get more people coming into those index pages instead of individual threads, and perhaps then they'd spend more time on the site before moving on. The result, however, was that my traffic from Google decreased by 50% and I'm trying to figure out whether it is because of the sitemap or not. I've redone my sitemap last week giving the threads (the content pages, which Google probably thrives on more) a higher priority, so we'll see if it changes things.

I'd be interested in seeing if this improves your search engine referrals.

I bet I'm more interested (and more desperate) than you are! Will keep you updated.

I would hope so