M-V-V-M
M-V-VM is a guideline, a pattern that developers can elect to use when authoring WPF applications. I like this pattern because it makes unit testing your application very simple. In fact, John Gossman’s litmus test for M-V-VM is that the application can be run without the UI. I also like this pattern because it is easy to use once the developer understands it.
Go to http://karlshifflett.wordpress.com/mvvm/
See also these related projects.