Leopard is looking really good, particularly the improvements in Mail.app. Will it be improved enough to make me ditch Thunderbird? If it still stores mail in a proprietary pain-in-the-ass format, then no. But if all the new bells and whistles work with IMAP and nothing stored locally, I’m there, man.
And of course, it’s about damn time they got around to virtual desktops. Looks like they did it pretty well, with a good-looking couple of pager options.