@Rory:

Agreed, although I’m not sure about the “files on the desktop” metaphor, not least because it causes confusion if you’re to take multiple screenshots in a series in which the desktop can be seen. Vista and Windows 7 take a step in the right direction with the “Snipping Tool”, which is quite nice, but doesn’t go far enough to make itself obvious (it should be *bound* to the Print Screen key that users are already so keen on using, unless turned off).