shurg.
I like even numbers. Double doors to me look so much nicer then singel doors.
Double doors look nicer, but in older Minecraft versions they didn't always behave as intended, and making them work with buttons or pressure places tended to be problematic. So until recently, single doors were just easier. And 9x9s (or other variants of the general box shape) are easy to build and easy to extend.
But, well, they don't look that great.
What's that texturepack? I've seen it, just can't quite recall which on it is...
Yeah, it's Soartex just like everyone else has been saying.
I've added a Steve's Carts tree farm and three fermenters to my base, allowing me to start using eight Biogas engines for power (my three Hobbyist Steam Engines just couldn't keep up any more). I'm doing my best to avoid non-renewable energy sources like oil/fuel, so I think a boiler run on biofuel might be my eventual next step. I also redesigned my sheep farm to use CC turtles and built a blaze farm (I got lucky and found three blaze spawners in the Nether, so getting a Tier 5 blaze spawner was pretty easy). Both the sheep farm and the blaze farm are blatant copies of Direwolf's designs, but hey, they work really well.