Lately I have been playing around with the VS2008 Beta 2 and building an interactive media application using WPF.  I have found the VS2008 designer quite buggy when dealing with WPF windows/controls at design time, which led me to start using Microsoft Expression Blend in conjunction with VS2008 - so far this has been a much better development experience.  

You can open your solution in both applications, and switch between them at will - VS for C# coding and xaml, and Blend for doing 'visual' wpf designing.

   

If you are trying to learn how to use Blend (like me), ContentPresenter.com has some really good tutorial videos that will get you kickstarted.

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