Visual studio and express editions have a nice Smart Tag support for auto-using statements to qualify a data type by including the using statement for that data type.
Though this feature is well known by IDE users, a little less known feature is the shortcut to get to it instead of hovering over the little underscore. You can press Ctrl+(.) (Press control and dot keys together from keyboard) to get the menu that shows all the available using statements or a fully qualified name for the data type.