I'm ready to buy the moment it's released.
I don't really expect anything to become available until after Leopard ships, as I expect Keynote, in particular, and iWork, in general, to be dependent on CoreAnimation and other 'under-the-hood' improvements in OS X 10.5, but I'd be happy to be proven wrong.
I start teaching again in September, and I'd love to be going 'on-stage' with the next generation of presentation software.
Truth be told, no software can make a bad instructor good, but good software can make a good instructor better.
Cheers