I also got my baby last week - and it is a 575 F1 !
So why have I answered the question 550 or 575 different than most of you ? I was really looking for a 550 when I started my search. I look at some 550's but I found not a color combination that I really liked or the cars were not in really good condition. One Ferrari Dealer really insisted that I take a test drive in a 575. I felt that the engine is notably stronger, but I did not like handling. That first 575 did not have the Fiorano package, so I had to try that too, and I just loved it. Then I found a car in the right color: blu pozzi with cuoio.
Prices here in Switzerland seem to be different than in most parts of the world. In this case, they are cheaper. Comparing cars with similiar milage and condition, a 575 is 10-20 % more expensive than a 550. I think that is ok, considering that you also get stuff like navigation, tire pressure monitor and xenon lights.
And yes, the GTC grill.