In ROX, the user can have multiple filer windows open, drag to pinboard and panels and so on. Toolbars, menubars, etc Screen space is precious. You either reduce the area available for showing the user's data, or you cover other programs. Add extra user interface features only if they are needed. Toolbars Toolbars are generally OK if they're small.
Users are more likely to investigate five tools than thirty.
A menu bar is slower to access than a popup menu, and wastes screen space. Status-bar, Preview panes, etc These are usually a bad idea, but it depends on the application. Put them in if they become necessary. The preferred method for giving commands in ROX applications is the popup menu. No time wasted moving the mouse.