For years I have been using the Radio Button control in many of my solutions (where it has been appropriated). When using the control it was usually together with the Group Box control. The following screen shot shows a common approach when using these two controls together and where users are supposed to select one of the three options. Typically one of the Radio Buttons is also pre-checked when the Windows Form is loaded.
When designing the UI and consider to use Radio Buttons the question we should raise is; when is the number of items relevant to the end users? My answer is when the users are about to make a selection, not before and not after that decision point. After the decision has been made the selected item should be viewed.
This lead to a new standpoint, at least to me, when designing UI; instead of a group of Radio Button controls we replace them with a Combo Box control as the following screen shot show:
When the Windows Form is loaded we have the same option as with Radio Buttons; to have one (or more) item(s) selected or to have no no item pre-selected. When the users have made their decisions the selected item is showed in the control. Consequently, the UI gets cleaner and the Windows form may even be down sized. Of course, the same discussion can be applied to the List Box control.
All in all, for all my future projects I will simple drop the Radion Button control and instead use the Combo Box control. Do You agree?