[MichaelG]

Interesting. I agree with the Zen feel of GTD, but one of the big implementations of GTD is the hipster pda, yep, notecards. The checkmark is pretty self-explanatory. I like the feel and actually had quite an opposite reaction to the icon. Not to quarrel with your impression, it's yours and legitimate, of course; but just to mention that I have a different reaction to it.