You've got to find what you love and that is as true for work as it is for lovers. Your work is going to fill a large part of your life and the only way to be truly satisfied is to do what you believe is great work. And the only way to do great work is to love what what you do. If you haven't found it yet, keep looking and don't settle. As with all matters of the heart, you'll know when you've found it.