Here is my post about this : http://forum.arduino.cc/index.php?topic=306628.msg2132669#msg2132669
Some people spent a lot of money to buy the official boards, but with the "wrong" official boards from Arduino.org, the drivers from Arduino.cc version 1.6.0 didn't work.
The normal Arduino Uno from Arduino.cc has a VID of 2341. The Arduino.org Uno has a VID of 2A03, which were not recognized by the Arduino.cc 1.6.0 drivers. The Arduino.org has additional drivers in the "drivers" folder for the 2A03 version.
This is really sad. New enthusiastic users might just as well buy the cheapest fake boards from Ebay. Preferably with the CH340G chip (which needs a driver "ch341ser.exe" from wch.cn).
There is nothing on the home page of Arduino.cc and nothing in the Blog about this. We (users of Arduino) should be informed properly !
I hope someone will take all the legal steps to solve this within a few months. Perhaps both Arduino.cc and Arduino.org should be stopped and a new Arduino team should be created. Dave Jones from eevblog should rant about this. To Adafruit and Sparkfun: this is your business, join together and force a solution. If possible, you both can be the new Arduino team.
UPDATE: The new Arduino 1.6.1 contains also the drivers for the Arduino.org boards.