One of the most important challenges that academics will face is group management. Although this takes many forms for graduate students, undergraduate assistants, and so on, I believe postdocs are a fairly "universal"—a professor hires a postdoc specifically for his group.
However, it's not necessarily clear what qualities to look for in a postdoc.
Does it make a difference if it's your group's first or second postdoc, versus the n'th postdoc?
How much weight should one give to letters of recommendation?
How do you analyze a publication record, especially when towards the end of the PhD, many papers are often still unpublished and therefore "embargoed?"
Are there any criteria that applies specifically to postdocs that might not be considered in, say, hiring for industry or business?