This is actually a really great question; mostly so because it offers "another" 100 years. This postulates many things. For one, that these are additional years that would carry with them the lessons learned from my life, things that I could carry forward into the future. So the short answer, is "transcendence"; the next level beyond Maslow's self-actualization.
With the wisdom of my learning years (ie those bumps and bruises I've made so far from bad and good decisions) behind me, it would reduce many of the self-imposed limitations I have about capacity now. That is an incredible thought. Not to mention, getting to know my great-great-grandkids!
And two, that I'll somehow have the health and presence of mind into my 150's that I might not otherwise have. It would suck to take you up on this offer, then get hit by a car and be left in a coma. :-/
But I choose the former, with appropriate caveats. With the extra time, wisdom, education, experience, perspective - all of those wonderful things that grow with age.