I started using GTD partially because I was sick and tired of failing to meet commitments I had made in my career and personal lives. That was a secondary motivation, however, because I know that most of my unhappiness stems from going through day to day struggles with no end goal, i.e. purpose, in mind. I believe that a certain level of stress and discomfort is acceptable if they are incurred while serving some greater purpose.
I have been using GTD for the past few months and it has helped me get control of my day to day tasks/obligations/projects/commitments, etc. Like many others, I feel that GTD has prepared me to tackle more complex goals like defining and working towards a set of longer term goals. I also realize that I have too much on my plate and need to cut back to focus on what is most important. The problem is that I have not defined what I call my, "life goals," so what is most important is partially undefined. I am at a point in my life where I need to make some big long-term commitments around family, for example, when to have children and whether to move to another part of the country and career, i.e. stay at current company, apply somewhere else, start my own business, or go back to school full time.
My current strategy is to start by defining my, "life vision," which is a high-level summary of what I want my life to look and feel like. I think this lines up to the 50,000 and 40,000 foot levels in GTD. The challenge I am stuck at right now is defining my "purpose." I know I am not alone in this. I am very interested in hearing from people who have faced this question and successfully answered it. What tools, books, exercises etc. helped you achieve the self-awareness that allowed you to define your life's greater purpose? It would also be helpful to hear from people who have tried some things that failed - what was NOT helpful and a waste of time in the end?