How Do You Measure Productivity at Work?

A system administrator at Slashdot wants to know what units of measurement he should use to document his team’s productivity to the Pointy-Haired Boss. While the question was pretty tongue-in-cheek, it got us wondering: how do you decide whether you’ve accomplished a lot or too little on a given day? Many answers will depend on what your role is at work, but some things will be universal. Give it up in the comments.