I don't want to hurt anybody's feelings here, with the headline I just wanted to catch your attention.
But still, I think immortality is not realizable nor desirable. The value of everything is determined by its scarcity, that is why I think even the possibility of immortality would lead us to a life more unproductive and less satisfying than ever. Why would anyone care to do a certain research, task or work if he has forever to complete it? Why would anyone bother to enjoy his life now if there are uncountable years to come in which one could finally realize his dreams?
Supplying too much of anything depletes its value. This holds true for money and this holds true for life.