Well, Leopard loaded on my work system in 1 hour 25 minutes. I chose to update rather than start over. All this worked fine. I have not found any apps that are dead yet and I have played with Spaces so far. Very slick and seems faster, but we will see how it goes at home.
I am still going to the Deer Park, Il Apple store at 6 p.m. tonight and waiting in line for my home version. I like the whole Apple new product experience and missed it on the iPhone, so I can't wait. Plus the first 500 people get Leopard t-shirts!
If you are looking to buy Leopard and do the update, here is a great site to review before you do the update: TUAW Guide: Getting Ready for Leopard I will be following this before I update my 12" PowerBook. I will post again about how this update goes later.