You can watch the WorldWide Developers Conference Keynote address from apple's site (requires quicktime). Having gone through the highlight's on many of the apple blogs, the most exciting news for leopard is that it's going to have a proper virtual desktops tool called spaces and some useful productivity enhancements to mail. I'm also looking forward to checking out the "time machine", a tool that enables you to recover lost files and go back in time to a previous system state. On the hardware front the 64bit Mac Pro looks pretty hot.