What's your favorite way to defend yourself from mobs?

There are different strategies and techniques for defending yourself from mobs, such as placing down a fence so that (cave) spiders can't attack you but you can attack them, creating a 2-block tall enclosure so Endermen cannot attack you since they're 3-blocks tall, building rail tracks around the perimeter of your base so Creepers can blow your base up, taming pets (like Ocelots and Wolves) to prevent Creepers and Skeletons from attacking you, creating pressure plate and hookwire traps (such as arrow dispenser traps), planting cacti around your base in a desert biome, etc.

Personally my favorite defense (not sure if it was ever fixed) is building rail tracks around my base. It's just so odd that Creepers can't cross rails, but I think it was designed that way to prevent mobs from blocking rails and getting into mine carts. It's one of the few and strangest defenses I've been using in a lot of my Minecraft worlds for a long time.