Empire claims that Neil Marshall, the badass director of great violent films like The Descent and Centurion, will return to Westeros for another crack at Game of Thrones. Marshall last directed the big Season Two battle episode, "Blackwater," easily one of the show's three most memorable episodes (the third of which, I must admit, I have not yet seen).
This time, he will have to trade in water and fire for ice and giants. Marshall has been hired to direct the final episode of Season Four, which will apparently cover The Battle of Castle Black, a multi-day struggle between The Night's Watch and Mance Rayder's army of Wildlings.
While the Battle of Blackwater was great both in the show and the novel, this one is way more fantasy based and potentially more awesome. I imagine it will be a lot more difficult to pull off as well.
We will have to wait an excruciating long time to see this, however. It almost hurts to know about it so early. The only consolation being that it will probably be worth the wait.