Is there a reason you're not using WPF instead of a Windows Form Application? The Kinect for Microsoft SDK samples use WPFs due to its stronger capabilities with displaying/dealing with visual elements. The learning curve isn't that huge to go from Windows Form to WPF imo, and there are plenty of blogs that can help you get started or answer most questions you'll have to start off:
Here's a list of WPF blogs: http://blogs.msdn.com/b/jaimer/archive/2009/03/12/wpf-bloggers.aspx My favorite is the 2000 things blog.
In WPF Kinect applications, there's typically an Image element in the .XAML side whose source is set to a WriteableBitmap property in the back-end code. On each Color Stream ready event (or any stream for that matter) you can write the new set of pixels to the WriteableBitmap and the WPF image element is instantly updated. I haven't tried using Windows Forms but I think it's a lot more work for a less-clean product.