I would not want to live forever, since I believe in heaven. I am one of those to live to the end of the world. Immortality, I would think, would eventually drive me insane. I can't possible imagine what I would become after so long, for good or for evil, even after 500 mio, let alone eternity.
It really depends on if everyone else also lives that long, or only me.

There is no doubt that I would be completly different.