This is a rather small and grainy picture, but it is a shot from the Blizzcon slideshow depicting "Shadowmourne", the next big legendary melee weapon scheduled to hit w/ Cataclysm.
It's blue, and I find it a bit interesting that an orc is holding it. People are talking about Thrall of course. Is he scheduled to help hardcore raiders whack Arthas before Deathwing awakes? Is that how Shadowmourne is birthed? I'm probably completely wrong here. Heh.
I didn't get to watch much of that part today, but thought some people would at least like to see the image.