After some consideration I once again used a service of one online store in my country that sends you the CD key in email right after they get the game in stock which should happen sometimes on the 13th of 14th. Overall it costs 43 EUR / $54 which seems to be a fair price for getting the game in advance. I got WotLK and Cata from them too and it's kinda convenient.
How about you?
Hope I didn't forget any major way in the poll.