One thing I encounter frequently is the argument that a meaningful life can only be derived from religious or metaphysical beliefs. I think this comes up because oftentimes the person making the argument had no meaning in their life until they found religion. I feel that I have found meaning in life without the need to defer to a metaphysical entity. I believe that the meaning of life is to continue living, growing, and improving. Life exists to beget new life, new ideas, and new creations.
So what does that mean on a personal level? It means that personally, you have to figure out your own meaning. One approach to do this is to ask yourself "What is my place in the world?", "What makes me feel fulfilled?", or "What would make me the best 'me' that I can be?". The problem with this approach would be the lack of a clearly defined personal meaning, or a clearly defined means of determining a personal meaning. The advantage is that the meaning I have found for myself is far more satisfying and personal than any purpose that a religion can offer.