Greenshot is a free screenshot program that I encountered on my job at a client. Download here

what it does: You can set it to quickly take a screenshot of a selected region.

How I use it: I have set the print screen button to activate Greenshot. It freezes the screen and let me select the region to get a screenshot. Besides that I adjusted the settings to copy my screenshot directly to the clipboard. This allows me to quickly capture something and paste it into my notes.

Great software, but it becomes pretty powerful when working together with Ditto (no, not the pokemon...).