It's official! Blizzard announced on their official site today that the WotLK expansion will be released on November 13th. That's 10 days later than other sites like GameStop, Best Buy, and Circuit City had been advertising though.
So now we know, and we have a definitive time frame to finish preparations for the expansion.
Also, Blizzard has finally announced what will be included in their Collector's edition (CE). Looks to be exactly the same as the Burning Crusade CE. Unlike the first expansion, I personally do not plan on ordering the CE.