Order it on battle.net. Unless you specifically want whatever comes with a physical copy, with Blizzard there really is no point in worrying about having the disc, the way they do things now. This is coming from someone who likes having the disc to go with the game. Since it all has to be married to a person's account anyway and has to be played with an internet connection anyway, and since it can be digitally downloaded at will, there's zero incentive to having a disc.