The disksys.rom is 8kb, compatible with FCEUX GX for Wii.  The root folder contains every rom published by Nintendo for the NES as listed in http://en.wikipedia.org/wiki/List_of_products_published_by_Nintendo.  Extra contains extras :3
Homebrew contains some wacky stuff, 1,000,000 Copies Published contains the roms that sold over 1,000,000 copies, the Translations folder is incomplete, suggest roms that need them!  The Vs. Roms folder needs Urban Champion, Wild Gunman, Volleyball, The Legend of Zelda and Gumshoe to be complete (links to those roms left in the comments section would be much appreciated!