I second the advice that you should consider more than one dealer. Your most powerful argument when negotiating the price is being able to say ( and really mean) "No thank you. I have a better offer somewhere else". That sentence can do magic and soften the stance of the most stubborn of GMs. And if you happen to be dealing with one who will not budge no matter what, you walk!
2012 X5 35d
2010 X5 35d