1.6.6 has its own problems.. Torches are permanent yes, but if your world was created before the Biome versions of the game, gods only know what kind of environment your gonna end up with.
My server is running the latest Bukkit with World Guard, World Edit, and Weather God installed and we still cant resolve any of the issues brought on by the Biome versions. Last night we moved our original world aside and created a second world. I'm not gonna give up on the original world though. I've got a couple thousand hours building in it, so does Smoothie, and Nick Degnan. Around the world the Biome updates have ruined a hundred worlds, and thousands of people work. Notch has GOT to fix this..
PS.. AND yes, i WANT TO BUILD A GREAT BLOODY AIRPORT AND HAVE aIRCRAFT IN mINECRAFT AS WELL. ( shameless plug to be kinda on topic )....