What is everyone's opening build?

Building air fabricators first is a poor choice.

Vehicle and bot fabricators use 1,000 energy per second.
Air fabricators use 1,200 energy per second.

http://pamatches.com/wiki/units/bots/fabrication-bot/
http://pamatches.com/wiki/units/air/fabrication-aircraft/

I love it when my opponents use Air Fabricators. They expand extremely slowly and have a weaker economy. It's also extremely easy for me to destroy them with just a few fighters. Even if you have more fighters than me, I'm still able to shoot down most or all of your Air Fabricators.

I like always do what no one else do.