Agent smiths differ from the other Agents

[spazztastics]

There's one thing that I always wondered about the Matrix Movies.. Agent Smith always (from the first movie forward) seem to have more consciousness then the other agents which made him a perfect arch villain. While the other agents was more unintelligent 'robot-like' and seemed to act only like a antivirus system which purpose was to keep the system clean from viruses (neo and the gang), Smith was always on a personal crusade against the humans. Everytime in the movies he seemed like he wanted to break free from the system so he could get rid of any human alive.

Which comes down to my question; why did Agent Smith had a greater consciousness then the rest of the Agents? Where there any system benefits from this, or was it simply because he needed to have a mind to be the arch villain in the movies?
I'm confused because the other agents seem like they don't have any own mind. They're just programs who are not either good or evil. Smith always knows about what the Matrix is and what his limits are, so is Smith maybe really a human and the only human of the agents?

Maybe Neo isn't 'The One', maybe Smith is? o.O

Any help clearing out of this matter would save me some more restless nights xD