In Epoch Five we will be constrained by little but our imagination.
Kurzweil talks about how our version 1.0, purely biological bodies, will be transformed into first 2.0 versions (nanobots added) and ultimately 3.0 (biologic-silicon hybrids with intelligence also in the web).
His first example is that nanobots will change how we eat. Just as in civilized lifestyles sexual activity has become more and more divorced from procreation, so in Singularity times eating will become more and more divorced from nutrition. The nanobots will take care of nutrition independently of what we eat. Eating will be done just for the pleasure of the experience.
Likewise, the other biologic systems, such as blood, will also be enhanced. There is little that can't be enhanced.
The computing power around us -- in our clothes and our living environment -- will also grow exponentially in capability. The computing power of the nanobots living inside us will also grow and their ability to connect to the web of external computing power will grow. Kurzweil talks about the ability of nanobots to monitor what individual neurons and synapses are up to.
The impact of this is the ability to become someone else. Another way to put this is "Sim Gone Wild".
One of those "questions that will be fascinating until it's answered"-questions will be "How long should I live?" Immortality of the thought that is in the world-wide network will become possible, and it will be possible to move those thoughts from one physical body to another -- and those body styles can be different. Truly body version 3.0!
From here he moves on to speculating on work and warfare and why we are likely to be the first intelligence in this galaxy (if there were others, they would have spread by us by now).
It's fascinating stuff.