Great question. I have tried to understand this myself without a good answer. Google chrome UI team had an article on how they didn't find good user controls

Great question. I have tried to understand this myself without a good answer. Google chrome UI team had an article on how they didn't find good user controls or windowing system for Windows and had to write everything from scratch. The chromium source was way too complex for our needs so we ended up not exploring it. Still open source GUI code. (So good open source GUI code in Windows has been hard to find, but that's a good bet). You probably want your app to run on both XP and 7 ? 8 is vaporware as a target platform for releasing and scheduling purposes. We started with Windows Forms for our work because we were familiar with the code. (We did use MVC pattern using MVCsharp). We meant to switch to WPF but we never made the leap. There are UI-controls you can buy (with source) which you can use as plug and play. There are a few popular vendors. Windows Forms still look ugly (lipstick on a pitbull kind of thing) WPF is supposed to be a panacea with XAML being markup and that letting you generate "fluid-UI" just like HTML with auto-resizing and scaling as in the browser for your web-app. I'd explore WPF and figure out a MVC-pattern library for separation of concerns. Hope this helps.