I asked people in Twitter from my Twitter account @mrcadman to take a guess at the top 5 most used commands in AutoCAD are. I received a wide variety of replies, and some were very close to the actual top 5 commands.
I checked the invoked command data reported by hundreds of thousands of AutoCAD users submitting anonymous CIP (Customer Involvement Program) data to Autodesk.
AutoCAD's Most Used Commands
My favorite of all AutoCAD commands comes in at number 6, UNDO.
If you are not submitting CIP data please consider it as it helps Autodesk know how our products are being used for future design improvements to save you time and make a better product.
Past blog posts on CIP and CER data:
Autodesk Research on Command Usage from CIP Data