Blizzard has released some launch night video from the Wrath of the Lich King release over on their EU site, and it looks like things were pretty crazy across the pond. There were costumes aplenty, and there were crowds in London, Germany, Spain, and the Netherlands. Plus, the video even has a nice appearance by the man/demon himself, as you can see above.
Unfortunately, the US site hasn't posted any such video yet, so while you can definitely read here on this site about all of the crowds and chaos that went down on this side of the world, there's no video to compare. My guess is that while the EU folks were definitely excited, over there it was more contained to the big events and the big cities, while over here in the US even small towns had lines outside the gaming stores.
But it was definitely a night to remember for WoW fans, no matter where you were.