It's a new project ! if your environment give you the possibility to work with WPF and Silverlight2, go ! May be it's the good project to let the team learn new technologies ? May be not ? If your strategy is to use Microsoft technologies go directly to WPF/Silverlight2. Of course your team will take some times to learn this 2 new technologies but if they know well .NET code, learning XAML will not be so hard. I had the same problem a few times ago. For some reasons I decided to choose WPF for my office application : > Powerfull way to build rich interface. You can do what you want depending on your imagination. > Powerfull way to represent and to manage Data (DataBinding, nothing to do with WindowsForm) > XAML is used in Silverlight2 and WPF application. Whith small changes your office application could become a web application. Your work is divided by 2. If you go to WPF and Silverlight 2 you will never come back to WindowsForm (sometimes I did nightmares).