One of my old keyboards had a shutdown key. I thought that was kinda handy, and through some geekery and my current keyboard’s multimedia keys, I created ways of shutting down and restarting my computer that are almost as easy:
Ctrl+Stop: Shutdown
Ctrl+PreviousTrack: Restart
To set these up in Windows, I added a few lines to an AutoHotKey script that I have set up to run when my computer starts:
^Media_Stop::
Shutdown, 1+8
return
^Media_Prev::
Shutdown, 2
return
The shortcuts were even easier to make in KDE, because it already has the software needed to pull that stuff off. To set them up, open System Settings and head for Keyboard & Mouse > Global Keyboard Shortcuts. Change the KDE component to "The KDE Session Manager", and you should find awfully hard-to-remember shortcuts for "Halt Without Confirmation" and "Reboot Without Confirmation". Change them to the easy-to-remember ones and you’re all set.