We shouldn't fear the inevitable. Once we have access to hardware that is powerful enough to support such intelligent AIs, it's only a matter of time until someone decides to create a malicious one. The only way we could realistically avoid this scenario is if we hindered our own technological evolution, but in any free economy it is extremely unlikely to have any end to technological advancements.

In my personal opinion humanity is extremely primitive in terms of intelligence and physical limitations, so we shouldn't be surprised when taken over by different form of "life" in the future.