My favorite is the Visual Extender which allows you to seamlessly add run and design time feature richness to any Windows based user interface. You know, the stuff that you usually have to spend hours adding to each control manually... a focus event here, a mouse down event there. With the Visual Extender, all that is a thing of the past. Simply place your controls on the form and add the Visual Extender. Then all you have to do is set the extended properties the component provides and you have a very slick, professional looking interface.
Some of the really cool features the Visual Extender provides to your controls:
-Windows Form Enhancements
-Control region image support.
(Visual Extender Off)
(Visual Extender On. A couple of clicks later.)