Wrath of the Lich King launched in numerous locations across the USA at midnight (albeit much of the rest of the world needed to wait until business hours). People queued outside Best Buy and Gamestop stores for hours beforehand (though 7-11 broke the street date and were selling copies a couple days early, we hear).
Several locations were particularly magical. A Best Buy in New York City and a Gamestop in San Francisco both sported particularly carnival atmospheres. Eurogamer says it was the UK's biggest launch and from the photos that's easy to believe. The French also had a blast with huge crowds and costumes.
All of the celebrations made one thing abundantly clear: We can all get in and enjoy our favorite MMOG with each-other -- even when we're not actually playing it. What the heck is gaming, if you can't celebrate it?