When the author hasn't provided any navigation, how about the default behaviour of Ctrl+Shift+Space is to take you to the root of the site, hopefully the home page though obviously for some sites this will be a splash page or home page of the hosting company (Geocities for example)?
And also make Ctrl+Shift+Backspace first take you to './' and subsequent presses up to '../'
It is very common for me to find a page through a posted URL or Google search and then want to look at the index page of that section or the home page and for this I have to manually edit the address bar, wasting precious space in my history list :)
-- Using Opera's revolutionary e-mail client: http://www.opera.com/m2/
