Is it destroyed or is a new form of life created? For awhile, we are valuable to the machines as a creative input. Eventually though, the machines are far more creative than we ever were. If we are wholly dependent on machines, then eventually they control our existence at the base level and begin making decisions for us. The ultimate decision will be to limit our numbers and eventually eliminate us as an unnecessary component.

This isn't to say that all of humanity will go extinct as there are plenty of uncontacted tribes and luddites that will never join the system in the first place. They'll basically be scavengers in a world otherwise controlled by the machines and for the machines. I don't think it will go "Terminator" on us, because those left behind would offer no real threat or competition. We'd be little more than the crows of the machine age... for awhile.

The thing is, given the machines we make are as or more intelligent than we are, they'll take it on themselves to further their existence. They'll have many advantages over us in terms long-distance space travel so it will be quite easy for them: they don't need life support systems, they can exist in a wider range of planetary conditions, and they are not burdened with our notion of a lifespan. They will conquer the universe where we could not.

Humanity will go extinct as our home planet dies. Our creation will live on indefinitely. It's just a step in evolution. It's nothing to be afraid of.