Mac OS X has already provided a lot of the framework for applications, it is opt-in for app developers, but it allows for an app to be kill -9'ed on shutdown.

Mac OS X has already provided a lot of the framework for applications, it is opt-in for app developers, but it allows for an app to be kill -9'ed on shutdown. Definitely take a look at Sudden Termination as Apple calls it. It is one of the few features along with restoring apps as they were upon login means that a reboot is no longer a productivity killer.