Another reason I like pcs: pressing command+shift+4 takes a snapshot of your screen and immediately creates a PNG file of it on your desktop.
If you press command+shift+3 it makes a crosshair, that you can drag to make a box, and when you let go it, again, takes a screenshot of the selected area and makes a PNG of it right on the desktop.
The crosshair even tells you location (in pixel coords.) before you click, and tells you dimensions (in pixels) as you drag.
:3