I've found a home on a free-for-all anarchy server, and I am looking for the best way to protect my home base.

I've heard the basic "build underground" and "cover your base in lava/water/ore blocks" arguments.

Assuming that above the Nether is out, and that occasionally an x-rayer will pass by – what is the smartest way you've ever seen someone conceal their Minecraft home base?