Become a MacRumors Supporter for $50/year with no ads, ability to filter front page stories, and private forums.
I doubt most will agree, but February 24th.

Why? Because the rumors say retail employees will be trained from 2/9 until 2/16. That same rumor suggests sales start +\-2 weeks later, so my guess for retail launch is March 6th. If it's released on March 6th, that means pre-orders start a week earlier: February 27th. The event would be the Tuesday before that, so... February 24th.

That is the most rational assumption, I can agree with this prediction as a reasonable announcement date
 
Register on MacRumors! This sidebar will go away, and you'll see fewer ads.