Take a look at Davy Brion’s critique of MVVM and his MVP In Silverlight/WPF series which discusses the MVP approach as an alternative to MVVM.
If you’re doing Silverlight or WPF, you’ve no doubt come across the MVVM (Model-View-ViewModel) pattern. It seems to be the most popular client-side architecture pattern used among Silverlight/WPF developers. I find the pattern to be highly overrated, and actually have some big issues with the whole thing.