In "Henry IV, Part I," who do you think is the more admirable character, Hal or Hotspur?

This depends from whose perspective you are considering these characters. If one is sympathetic to the Earl of Northumberland, then his son, Hotspur, is the more admirable character because he is a warrior, quick to action. If, however, you sympathize with King Henry, then his son, Hal, is the more admirable for he is more thoughtful, and stately in his own actions and in his behaviour towards others.