I actually just finished playing Minecraft for the night (made a diamond Inky from Pac-Man and a glowstone Triforce) and love the game.
For the first 15 minutes, you're hoarding resources, trying to figure out how to survive, and then you'll probably die.
Getting it right, and surviving that first night, is a relief, and building that dream house out of stone, wood or dirt (I did, my house is like a micro-mountain right outside a lake and it looks really nice with all the paintings and chests inside).
For a game that quietly popped up from way off left field, it's an amazing game that deserves most of, if not all the praise it gets.
Kudos to Notch for making Minecraft and I hope that it only gets better from here.
Beta's pretty good though.