It *is* a huge deal. I just picked up my wife's new X5 Thursday and it's the first time...out of 8 BMW's purchased.....that I put no money down. At .9% there was no reason to.
I'm tempted to go back and buy either a 135i or a 335i, but I have a two car garage and there's no way my 2006 M3 is sitting in the driveway!