For throwing together a GUI app, C#.NET is actually pretty handy. Here is my demo proving that C# isn't all bad - that is pretty quick and effective. Note that you don't need to use the visual designer at all, and that is what I would do for a larger scale project.
For larger scale projects, XAML is pretty interesting too. I used it at work this summer.
Why I like it:
On the other hand, here are the reasons why I still believe .NET is not the answer: