Windows - Screen Capture tools

I have previously seen and used proprietary screen capture tools, where you can take your mouse, and select an area of the screen (on any GUID or even an area shared by one ore more GUI's), and it will capture that image so you can place it into a PPT or Word document.  It was quick and simple to select and cut anywhere, and easy to paste to a PPT.

Does anyone know where I could download a freeware version of such a tool.  Does anyone hae a favorite?

Thanks

Does anyone have a favorite