Minecraft creator Notch has posted on his blog that the game will, if all goes according to plan, officially "release" on November 11 of this year. He notes that "the version we deem as the 'full version' won’t be very different at all from what the game was like a week ago ..." So, think of it as a morale booster.
"We’ll keep adding features after the release as well, so it’s really more of a milestone when we finally get rid of the Beta label, and some kind of goal for us to work towards," he writes. "It’s the same date as a few other games and movies, and the one I’m the most excited about is Skyrim, so that will be a nice reward for me if we actually manage to hit that date!"
As for the achievements- and statistics-introducing 1.5 update, release next week is looking likely. Bonus: it'll add weather effects, including things like periodic rain/snow fall, ice regrowing in colder biomes, and even thunderstorms.
Thunderstorms and creepers -- potentially at the same time. Shut. Down. EVERYTHING.