First off I am not a millionaire (yet). However, the concept of living on and on is something I view as scary, for reasons I do not wish to elaborate. I also believe that eighty years is more than sufficient time to live a life and accomplish all that I want to.

Also, rather than donate to a research which could possibly extend my lifetime, I would donate to organisations which are already enabling people to live better lives than they could otherwise. Personally, when I rise to a position where I can afford it, I would start sponsoring a kid's education every year. That gives me the satisfaction of knowing I am improving someone's life in some way.

+1 for research improving quality of our current lifetime, especially in areas of great need.

Also, aren't you the least bit curious what happens after your expiration? Not that I think I'll be joining past friends up in the clouds playing a harp but absolute nothing is about impossible for me to imagine. In that sense it seems silly to pursue the goal of extending life when you could use that time/energy enjoying it and anticipating what comes next.