A well-made base is your life. It houses you, protects your items and keeps out the hordes of dangerous mobs that haunt the shadows waiting for you. But how to build it?
This is probably your main room. It should have a crafting table and chests full of common crafting materials (Cobblestone, iron, wood, diamonds, redstone, Sticks, etc.) This can also be combined with a smeltery.
This room is full of Furnaces for smelting food and ores. There should be chests full of fuel and items waiting to be smelted. Consider automating the operation with Hoppers; however, be warned as Hoppers don't give any smelting experience. It's a good idea to keep this room near your animal farm so that you can easily grab raw meats to smelt. A minecart track from your mine is also advised. This room can also be combined with a crafting room.
This is for enchanting your weapons, tools, and armor. It should have an Enchantment Table surrounded by Bookshelves and maybe an Anvil for using Enchanted Books. Remember, a minimum of 15 bookshelves is required to get a maximum enchantment!
It's best to have a safe place to sleep so that a minimum amount of mobs spawn at night. The bedroom should have a Bed and be made of a strong material (Obsidian or End Stone are best) but most stone or brick types work as well. Avoid Sandstone and Netherrack, as they have low blast resistance.