Last night's beta patch implemented a number of new sound files, but this is certainly the coolest: King Genn Greymane, leader of the Gilnean people, now has unique lines of dialogue. While working through the worgen starting experience, it's quite strange to hear King Greymane talking about [spoiler redacted] before you ever experience it first hand, but it's cool nonetheless.
Gilnean NPC Lord Darius Crowley has received a line of his own as well. He gives a hearty, "We will prevail." Sadly, that's the only line he has so far, and the sound quality on it is far worse than what we've heard so far in Cataclysm. He probably isn't finished and hey, that's OK! It's a beta.
The video after the break, for people who don't mind being spoiled.