K is for Kings

Everyone likes kings except for the subjects of the kings (usually).  Monarchies are just plain interesting.  The dynamic between king and kingdom, king and subject, king and rival kingdom is sophisticated and drawing.

Typically kings only appear in fantasy, and perhaps alternate history, out of the speculative genres.  I think that it would be interesting to see more kings (and queens) in other genres.  Kings (and queens) in space?  Sounds awesome.

When using a monarchy, pay close attention to the impact of such a government on a country.  The social system in the country does not have to be feudal, though it often is.  Taking a king and planting him at the top of a Congress could make for a very interesting system (like England had historically, sort of).