I will say this: I am totally okay with medical science extending my life as far as possible, as long as it includes a corresponding amelioration of the affects of age (i.e. I don't want to live to the age of 150 if it means having the physical state of a person who had lived that long naturally). I can always step in front of a bus if I get sick of it all.

Interestingly, the "break-even point" for life expectancy vs. the rate of increase in life expectancy will be surpassed in our lifetimes if medical science doesn't run into some kind of hard barrier. When that happens, medical science will be increasing the average life expectancy by one year or more for every year that passes. That means theoretical effective immortality until the rate of life expectancy increase drops off for some reason (or until your insurance won't cover the longevity treatments).