Please consider the following in terms of both usability and aesthetics:
Do you prefer a global navigation menu on the main page that shows up in the same location of every page on the site? (That is, the same navigation menu on every page.)
Or do you like for each page linked from the main page to have its own navigation menu that breaks down that link further? (For example, I click on "Candy" on the main page of a site about junk food. When I get to the Candy page, I see a menu with "Chocolate Bars," "Taffy, "Hard Candy," and so on.)
Are there some general guidelines in the web design community?
I second that. In all applications, the menubar has a constant number of members. Some may be disabled. Only context menus are localized for that specific context. I believe that the web should retain that.
However, I'm curious if one can bring to the web, and still be accessible, the navigational elements of Office 12. It has no menus, only contextual toolbars.