I read today that December was the best month of 2010 for car sales. I don't know what accounts for that, though. 2009 was the best December in recent history.
I have always heard that too, though it doesn't make much sense. I would have thought December was a month when people avoided major financial commitments!
I once dated a car salesman and he told me there are lots of deep discounts around in December. This could be a major factor to consider, along with the abundance of xmas spirit perhaps?