"Milk's favorite cookie" was developed in 1912 and originally made to target the British market to spice up the "biscuit" world. (Ironically, when I was over there, Oreos were fairly difficult to find. Wiki, however, says that a major grocery chain started carrying them in May 2008 and Kraft foods is now distributing Oreos all over the UK.) The sandwich cookie has held a variety of official names -- "Oreo Biscuit", "Oreo Cream Sandwich", "Oreo Chocolate Sandwich" -- but none of the names or varieties have taken away from the goodness that is the Oreo cookie.
There is one question that always looms around the Oreo: what is the proper way to consume the delicious cookie? I haven't found the manual, but I can tell you how I do it: twist off the top, eat that side, lick off the cream, eat the bottom cookie. How do you eat your Oreos?