The first official release of Minecraft will be coming out on November 18th, 2011. The release will be called Minecraft 1.0, and it is the equivalent to Minecraft Beta 1.9.
There's too many changes for me to go over. I'm going to just link the Minecraft change-log for this information.
http://www.minecraftwiki.net/wiki/Upcoming_featuresHowever, this release of Minecraft introduces an ending to Minecraft:
http://www.youtube.com/watch?v=-0a0mtetKt0Now don't get me wrong, I really like giving Minecraft an End boss like this. However, it makes me worried that Mojang Studios spent too much time making this boss instead of fixing bugs.
I'm going to guess there will be three re-releases after the official release because of bugs. While the last few releases have been fairly stable, this is a very large release, and I don't think the last month was enough for bug fixing this game.