Cybermen and Daleks

The Cybermen are already here
http://en.wikipedia.org/wiki/Cybermenhttp://www.businessballs.com/cybernetics.htm
In "The Age of Steel", the Doctor is able to defeat the Cybermen by shutting down their emotional inhibitors, enabling them to "see" what had become of them. Their realization of what they had become led them to either simply shut down out of sheer horror, or partially explode.

Daleks are organisms from the planet Skaro, integrated within a tank-like mechanical casing. The resulting creatures are a powerful race bent on universal conquest and domination, utterly without pity, compassion or remorse (as all of their emotions were removed except hate).
http://en.wikipedia.org/wiki/Daleks