The impression I got from the keynote is that Leopard is somewhat 64 bit but not "fully" 64 bit. What's the deal with this? They did not just come out and say it is fully 64 bit. I have a fealing my PC buddies will pull some reason out of their hat that my favorite OS (OS X) is not as close to 64 bit as Windows XP/Vista is. Can anyone explain this to me? Is there nothing to worry about?