A funny title but I think we all ask that question many times. I know I have. One common misconception is that we make a choice when we are young and we are stuck with that choice forever. I do not for one minute think that is true. I think and believe that we are always becoming and can make many adjustments along the way. In a previous blog I shared some of the changes I have made in my working life, http://pxltd.typepad.com/project_x_discussions/2006/10/career_change_s.html
I think we all need to keep looking and evaluating. The key I think is "to follow the path with the heart." The difficulty I have found is to find that path. My current suggestion is to trust your intuition and gut feel. As you embark on the change do not turn your back on who you are now and what experiences you have. Build on your current assets instead of making a dramatic switch. In addition you need to be somewhat bloody minded about the potential for success. If you wish to make a change, talk to people who are doing similar things.
I remember somebody I worked with and was a successful IT consultant decided to become a teacher. Instead of teaching based on her training and experience she decided to go back to teachers college. After she finished she got a job teaching in high school and found she hated it and went back to IT work. I think a better strategy might have been for her to look for a job in the IT world that involved teaching. The transition would have been simple and she would have found out how much she liked teaching.
Somebody else who was unhappy in his current profession took career counseling and decided to make a complete break and go in a different direction. The field he chose was very difficult to enter and after banging on doors for a long time decided to go back to his previous work. Maybe a better strategy might have been to try to make smaller change and see if it took him in the right direction. The dramatic shifts mean, I think, is that you are turning your back on who you are. Maybe by being more creative, you can make a change but in the context of your current background.
However my point is we are always in a state of transition. The question of "what do I want to be" is always present. Do not think that because you are asking the question that you are unhappy where you are. Maybe it is simply a matter of attracting some changes in your current situation.