To be specific, I've always loved Snowy Taigas! The trees, the wood, the mobs, everything! I like building my houses near a group of foxes. It's funny to see them pounce after chickens or whatever and get their heads stuck in the snow. If I had to choose a second favorite biome it'd be Oceans, especially Coral reefs. Pretty, and when I want to make an underwater base, that's usually my go-to underwater biome.
