In Roger Zelazney's (wonderful) short story "For a Breath I Tarry...", the representation of the side of "good". It is Frost's superior, the only one he must answer to (for an explanation of why Frost is a "he", see the story's node).
Set high in the orbit of Earth, Solcom oversees the rebuilding of Earth, awaiting the return of man. It was the original computer for the job, from back when humans still roamed the land. An errant missile (or solar flare, depending on the version you have) messed up Solcom's programming, which invoked a clause in his opponent's programming. This caused Divcom to awaken.
Neither computer is actually "good" or "evil" because they both have the same plan: to rebuild Earth for the return of man. The only reason Solcom is said to be the voice of good is that it is Frost's boss, and thus defended by the protagonist. Some of the best parts in the story result in Frost realizing that Solcom could be mistaken or perhaps misled. | 
