Undervalued PPC Metrics: CPI, BR, Estimated columns

As a classicaly PPC trained monkey I learned to have my first basic set of columns. 
Clicks, Impressions, CTR, Cost, Avg position, Avg CPC, Conversions, Conv.rate, CPA, Impr.share. 
Well we all were in a way. That’s the way how we and our colleagues did it, and how we see it from the famous PPC blogs. However it’s a good base versions of the statistics overview, sometimes it can be blinding to be open to  slightly unconventional metrics, that are in fact useful to have more insightful information.