So you're thinking of creating a villain ...

... then you may want to read I, the villain at Brandywine Books. The reason Macbeth is more interesting than Richard III is that Macbeth doesn't set out to be evil -- and he retains certain redeeming qualities (his tenderness toward his wife, for instance). Which makes his last bold, desperate plunge into combat almost admirable. Richard's character is as grotesque as his physique.