Minecraft wiki entry for Best_biomes_for_homes, associated text: Lots of wood, which is a resource both new and experienced players require, due to its being the foundation of many essential crafting recipes.
The hills makes for good scenery.
Though normal houses may be hard to build, a treehouse is always a good solution.
The density and low height of treetops can provide a useful alternative mode of travel, especially at night, since spiders cannot climb past the leaves and other harmful mobs cannot find many ways to follow you - especially since they cannot jump over small gaps between trees. Just don't fall down!
Has a small chance of being a "flower forest", and in that case, the biome will be filled with exclusive flowers that are great for decoration and dyes. Also, rabbits and bees can spawn.
Is hidden and harder for players to find or attack you on servers.
Wolves can spawn, making good companions and bodyguards.
A plains biome is often nearby.
The grass color is vibrant and green.