UPDATE - a couple of people pointed out that the video link wasn't working anymore, but it seems to have been reposted here.
Back in October, David Allen gave a talk on Getting Things Done at Google, called "GTD and the Two Keys to Sustaining a Healthy Life and Workstyle," and now the video clip's available on YouTube. While this is definitely a worthy watch for GTD followers (or those who aspire to be), if you don't have a spare 45 minutes, the two keys are:
Control: Conscious focused engagement, aware of all options at any one time and place Perspective: aligned and clear about decisions, directions, and priorities.
All in all a nice GTD primer right from the horse's mouth. Thanks, Steve!