Minecraft Official Website – the home of Minecraft
Notch’s Tumblr – important updates and some other stuff by Notch.
Docm77’s Minecraft World – Docm77’s website, loads of great content about Minecraft
Minecraftaddict on Reddit – MinecraftAddict’ reddit thread. Lots of great minecraft engineering
Zhulslab on Reddit – Zhulslab’s reddit thread, another great source of Minecraft inventions.
PureBDcraft Online – The home of PureBDcraft. One of the most amazing texture packs out there!
Crafting an Empire – McFly’s blog chronicling his progression on building an empire in Minecraft.
Dead Workers Party – the Dead Workers Party, creators of Control Point, a TF2 related podcast, and The Shaft, a Minecraft related podcast.