Okay, people who have ever hired someone, especially new graduates, for a legal job: What makes an outstanding cover letter?

A couple specific questions:

Do you see the cover letter as an opportunity to get to know the applicant personally? Should it include personal info (a life experience that drove them to this practice area, for ex.) or is it best that they stick strictly to career info?

Aside from baseline competence (grammar, structure, etc.) is the quality of writing something you actively assess? Do you see the letter as an opportunity to quickly transmit basic info, or should it almost serve as a writing sample?