"I Don't Know" is the usual response to this question. Have you ever noticed that sometimes the easiest questions are the hardest ones to answer? Many of us spend the majority of our lives not really knowing what we want. Some friends might recommend that to start this process you should begin a list of what you don't want which will then narrow down your answers and options. I guest this can help as long as it doesn't move into the ridiculous such as; I don't want to be hit by a car, or I don't want to lose my job, etc.... There aren't very many people that I have met that want these or other things like them.
So how do we find out what we really want? To have your answer matter you first have to know yourself. If you have a good idea of who, not what, you are and what matters to you then you are on the road to success in this venture. It helps if you want things that benefit other people besides yourself, this way you can gain almost instant support, not to mention immense personal power.
Creating power, stability, and happiness and such are directly related to what your passions are. If you dedicate your being to achieving these then you are much closer to figuring out what you want out of life. Love plays a large part in this because your capacity for love will help to guide you to your passions. Human beings want a lot of the same things in life and the degree to which you can commit yourself to them will determine whether they become reality or just another unfulfilled dream.