The tutorial to install Leopard on a PC is very experimental and things might not work the right way simply because it is still early days in hacking Leopard to work on PC's. So, do it at your own risk.
Adobe Flash Player is an advanced client runtime for delivering powerful and consistent user experiences across browsers, operating systems and mobile devices.
Coda 1.1 have a bunch of Leopard-specific fixes including better Spaces support and plenty of UI improvement to bring it in line with Mac OS X 10.5. Coda, of late, is my <em>de-facto</em> development tool - it is a powerful Web Development Application.
The most important new feature added in Leopard is undoubtedly Time Machine, Apple's attempt to encourage the vast majority of users who never, ever routinely back up their data to change their ways. Time Machine automatically backs up a Mac's files to a separate hard drive (internal or external, though external is certainly safer and more convenient) or a network volume being shared by another Mac running Leopard.