well since I've built it on a hill I have already 3 or 4 cellars without hitting any cave. (I needed stone for obvious reasons)
But just for fun when I had still monsters in the game I dug a hole until I reached a huge cave and tons of monsters. End of story.

I didnt know you could make gates on this version. Got a fuckload of creepers waiting on my doorstep.

the bloodthirsty murderous spiders in my game that stalk and pounce on me say otherwise :) 

they also like to stand on the trap door to my roof breathing heavily fogging up the glass making it impossible to get up there -_-

Creepers are harder to kill in beta 1.6.6.

Never killed one. They explode too fast and I don't have a bow yet. (one spider web missing)

Quick piece of architecture there;

Also managed to convince a friend of mine to buy it like just now, so he's derping around in the background.. After dying 3 times to a creeper haha.

I went for the modern "castle that looks like a face" look.

Best mob defense ^^

Looks like an exact copy of my castle. I should sue you, you dirty thief !

I suggest do what I did for my PC version make a castle in the sky, it takes cares of almost all the problems a ground castle has.

look nothing alike trololol