Here. If you haven't seen it yet, you should check out Magic: The User Interface Library for .NET. It's got a ton of the UI stuff you always want, e.g. docking windows, menus with graphics, control styles and tons more. And the price is right -- it's free!
BTW, there is some overlap in the UI department with Genghis [1], but Genghis has some other non-UI stuff worth checking out, too.
[1] http://www.genghisgroup.com
