I think I've found a problem that some people may stumble over when typing themselves. Socionics is about information metabolism and intertype relationships; the type of information you like to produce and receive. Therefore, if you spend all of your time thinking in a certain way, but don't wish to share those thoughts with others, then this thinking means nothing in terms of the socion, because it doesn't affect your relationships. (For example, if I'm interested in a girl, I might spend a lot of time thinking about my feelings for her. However, I might not want to share these feelings with anyone. I don't think that this would make me an ethical type.) Further, if the complement of this type of thinking is not what you enjoy receiving, then it means even less, because it is also a theory about the type of information you enjoy receiving from others in your relationships. Therefore, if you want to type yourself based on the intended goals of socionics - to determine how you relate with others - then you will look at the information that you like to produce and receive, not simply what is often on your mind. However, it is possible that you have some other goal in mind. In that case, you are, of course, free to type yourself based on any criteria that you want (but don't try to apply your self-typing to your relationships).
Jason