I appreciate all your responses and insights about the subject matter.
Once again, I want to make it clear what defines us. It is our "life's memory". that makes us "Us", making us unique from anyone else. A person with a healthy memory can acknowledge his own identity & existence, recalls his experiences in life, and uses all his skills and knowledge gained in his life time. If our memory fails severely, all above mentioned capabilities will be denied.
The future holds limitless possibilities, if by chance the Scientist of the future can harness the power of NANO tech, it would revolutionize eveything. Creating the "Super Micro Chip" will be the next big time. Considering all other factors constant, the Super Micro Chip can perfectly records our memories since its installation. Thus, we can preserve our very existence through "Recorded Memory". This perhaps is the key ingredient of immortality. Our original bodies might perish but our "Recorded Memory" lives on.
With the perfection of Human Cloning and Stem Cells production, you can retain & repair your bodily features and functions. These bodies are merely vessels and it needs the "Micro Chip" to operate. Immortailty in the sense of continuity. Yet again, please bare in mind, that my theory can't be materialized overnight, perhaps it will take another thousand years or so to make this possible.
A 1000 years from now or before our Sun's Supernova (about 2.5 Billion years from now), the problem of over population is history. By that time, humans have already found "Earth-Like" planets where everything prospers like our Earth prime. With our Immortality we can explore the universe unbounded by time.
Some of you critics might say; "Does your Immortality Theory means that one will also endure Hunger, Anxiety and Depression for all eternity?".
I would say, I will eliminate hunger by incorporating "NANO Clorophyll" in the human cells. Future humans will simply bask on the Sun with photosynthetic abilities. However, there's little we can do about Anxiety, Sadness and Depression, that's the joy of being human. The players may change but rules remains the same, "One must experience sadness to know what is joy, Defeat to know what it victory".
Also, the Super Micro Chip doesn't only records your life memory, but you can also download skills (Cooking, Playing Guitar, Martial Arts, Drawing), Foreign Languages, Knowledge and information.
Isn't that awesome!