Sustainability Metrics

I'm heading to the New Metrics of Sustainable Business conference in Philadelphia next week.  A few questions for the experienced folks in this community:

Which, if any, sustainability-related indicators do you measure at your company?

Some companies are interested only in relatively simple metrics like measures of the energy effectiveness of production (kWh / unit of production, energy cost / COGS, waste disposal costs / COGS), measures of equity (board diversity, managerial diversity, Gini index).  Other companies find it valuable to delve deeper with a broad set of sophisticated metrics like the GRI, or IRIS frameworks.  Many companies have found the simpler metrics translate directly into bottom line savings rather quickly (Walmart is a great example).

What is your experience?

Given your experience of the challenges with financial reporting, what advice would you have for folks promoting a particular set of sustainable business metrics?

US Companies didn't always have the sophisticated financial reporting that they have today.  Much has been done to improve both financial and managerial accounting so that investors and business managers have a clearer sense of what's going on.  This long and challenging road no doubt has lessons that can be readily applied to sustainability reporting. 

What hard lessons from financial and managerial reporting do you think sustainability reporting could benefit from?