I think the Ubuntu installer should include one more page to allow users to select their preferred system of measurements and default paper size. I live in USA and at the installer I selected the largest city near me and it set the measuring units to imperial, but I hate imperial and would like to use metric. The Ubuntu installer should display a page similar to this after you select your location. On this Page the installer should already have everything marked for the most probable to be used, ie. imperial in USA, but should still allow you to choose the alternative, ie. the metric system in USA.