The flaw in GTD priortizing
Best post on this:
"I think you should have the discipline to make the four criteria work for you rather than being controlled by them. When there are important, high priority, next actions that are key steps in achieving your 10,000, 20,000, 30,000, 40,000 ft and above goals, you simply cannot let the four criteria get in the way. You need to use the four criteria as a checklist of things that need to be in place in order to complete your high priority items."