I am leaning towards Caliburn.Micro simply because it seems to be the most popular "lightweight" MVVM framework, but I was wondering if anyone had any experience with it or others (or if they are using none at all) before diving in.
My main requirements would be that it work with Visual C# 2008 Express, allow for targeting .NET 3.5 (and easily transition to .NET 4.0), allow for WPF Windows to be created, displayed as a well-behaved modal child dialog, and destroyed inside the ArcGIS Desktop applications, and provide logging, file open/save dialog, and message box services.
Looking for light-weight, minimal dependencies, promotes best design practices, etc. Everything else would be pretty much icing on the cake.
Or does everyone use Windows Forms still? :)