Question for Everyone - What are your Agile teams measuring and/or reporting on?

What are you finding to be the most difficult thing to measure? We know that adjusting from typical project management measurements to Agile measurements can be hard for the rest of the organization. What out-of-the box reports are you using? And, even better, has anyone created a report or chart for their Agile teams that has been particularly helpful?! We'd love to know.