I loved the way the old StarOffice behaved: a toolbar wich adapts to whatever you are doing at that moment. I saw this concept previously at CorelDraw if I recall correctly. Inkscape does also the same. In old StarOffice, it had the problem that sometimes you had several available toolbars active to switch among with an arrow button (that was not nice). Inkscape is almost doing what in my opinion a GUI for that kind of app should do:
1. Several global-use toolbars.
2. One specific-use adaptable toolbar.
3. Dockable dialogs (see Inkscape path/fill properties), for complex and repetitive tasks.
4. Menus for the following reasons: backup of tool-bar options, hierarchical organization, optimal space use, easy keyboard navigation and keyboard shortcuts reminder.
(Inkscape just fails a bit since some dialogs are not dockable yet, but does scroll-docking, side-by-side docking and tabbed docking).
I've never used ribbon thing but, correct me if I'm wrong, they are placed on the top zone, which is not a god thing nowadays monitors tend to be landscape proportions, specially for text-editing. Dockable dialogs are nice in this sense.