GTD implores you to NOT prioritize tasks in any written form. I understand the reasoning behind this and would never try to do an A, B, C or 1, 2, 3 priority for Daily or Weekly tasks. However, let`s be real here, there are always things that are more important than others in your day, but they are not tasks.
But how to keep track of them?
I`ve studied Hyrum W. Smith, Franklin Covey, and Anthony Robbins` time management programs. The thing that hit me most about the latter two is the idea of "outcome."
Outcomes are not linked to one particular taskbut feelings, accomplishments, connections, etc. you want to achieve out of a certain task or set of tasks.
Since these are things I naturally want to keep in front of me (and do not want to introduce another list or view) I write must outcomes in my Task list and mark them as "High Priority."
Someday/Maybe ideas, tasks, actions that are not part of any current project are given no due date and prioritized as "Low Priority." This makes it easy to sort/filter these items in Outlook and my PPC.
Priority is completely time relative. Even though, "take my family to Cancun" is very important, it may not be important this week or month. So, you could mark it as Low.
Be sure to reevaluate all of your High, Med, and Low tasks during your weekly review.