I just found this excellent article that suggests 40 possible ideas about the meaning of life.
In reviewing these 40 ideas I think the most valid options are existential freedom and nihilism. Both of these philosophies suggest that man is alone in a meaningless universe with no predetermined meaning or purpose in life. They represent a good news bad news situation. The bad news is that man has no predetermined meaning or purpose. The good news is that we are free to create our own.