I envision a future where mankind has reinvented itself through 'self evolution'. Some day you will be able to 'be' anything we can imagine. Not only will we live indefinitely, we will be able to take any form we wish, and live a multitude of lives limited only by our imaginations. 
This may not be so far out! When we hit the "Technological singularity", (an "intelligence explosion", suggesting that if machines could even slightly surpass human intellect, they could improve their own designs in ways unforeseen by their designers, and thus recursively augment themselves into far greater intelligences. The first such improvements might be small, but as the machine became more intelligent it would become better at becoming more intelligent, which could lead to a cascade of self-improvements and a sudden surge to superintelligence (or a singularity).) we will, by using the machines yet to be invented, be able to speed up, and control the path of human evolution. We will develop into a new "post human" form.