As far as tradtional desktop apps go, over 40% of Adobe's Lightroom was written in Lua. If you read the front matter in the link then you'll see their forward t

As far as tradtional desktop apps go, over 40% of Adobe's Lightroom was written in Lua. If you read the front matter in the link then you'll see their forward to the book. Wikipedia has a list of Lua apps as well. It seems fairly incomplete... if I recall, Lua has gone into space on at least one commercial satellite :) Lua is the scripting language for nmap, wireshark, various embedded processors such as lego mindstorms, and dozens of high-profile games.