I’ve known about the Command-Shift-3 (and Command-Shift-4 in OS X) shortcut to take screenshots of a Mac for years. That said, I always wanted a way to save the screenshot to the clipboard. The answer was right there in front of my face the whole time!
Command-Shift-Control-3 and Command-Shift-Control-4!
Knowing this would have saved me countless hours in the past!
tow.com 
Greate for Mac!
In windows I use a smart tool named Quick Screen Capture from http://www.etrusoft.com
I use Snagit for a while but it’s too big to use. http://www.snagit.com
Neat Adam! Thanks, Peter