The moment you have all been waiting for is here.   The #1 change to NFPA 80 , 2013 edition is not a change to a specific section or word, but rather to an entire chapter.  The #1 change encompasses some specific issues that I have included in the top 5, but is a change that will affect nearly every user of the document.
#1:  Rewrite of Chapter 5 - Care and Maintenance.
For many users of NFPA 80 , you may remember that Chapter 5 was new to the standard for the 2007 edition, when the document when through a complete rewrite.  At the time, the new Chapter 5 expanded the requirements related to the inspection, testing, and maintenance of fire doors and provided the now famous requirement for the annual inspection of fire doors.
After existing for two cycles, it was time for the committee to further revise and clean up the Chapter. For 2013, not only has Chapter 5 been revised editorially, to better organize the material, technical revisions have been made to the requirements for field modifications, acceptance testing of opening protectives, who is completing annual inspections, record retention for inspections and tests, and clarifications throughout the chapter that its requirements apply to fire doors, fire windows, and fire shutters. Many of these technical changes solve issues that have surfaced since the Chapter was published in 2007.
The result of all the changes to Chapter 5 is a more technically accurate and user friendly Chapter that contains information so important to the users of NFPA 80 and to the fire doors and opening protectives being inspected, tested and maintained.
I encourage you to check out the new edition of NFPA 80 and read all the valuable changes that have been made by the Technical Committee.