As fascinating as the crystal skulls are, I don't see any evidence that finding all of them will have any bearing on mankind's destiny and the 2012 date, while fun to talk about, is pure speculation at best. It's simply when the Mayan calender changes and there's no reason to believe that anything big will happen. Granted, it COULD, but I doubt that it will.
In The X-Files it was revealed that December 22, 2012 is when an alien invasion and colonization of earth will occur. Now THAT would be interesting.