I think that the prospect of living forever would change the way we live our everyday lives. Death is a big part of life. We scramble around as fast as we can in an effort to build a life for ourselves, knowing that we don't have much time to do it. We take classes, persue careers, acquire wealth, have children, and do everything that we do with an eye to our legacies, because we know that one day we won't be around anymore and only those things will speak to furture generations for us when we are gone. If we were able to live forever our entire prospects would change. We would no longer need to run a rat race everyday in an effort to amass the things of life like trying to collect water in a sieve. I think it would be very liberating.
I'm all for the "Tuck Everlasting" brand of living forever myself.