Qt Creator has a very good GUI designer that is very much a drag and drop designer, if you want to add a handler for say when a button is clicked, that is 2 or 3 mouse clicks away.
Actually in Qt Creator you can create a "Qt Gui Application" project, and with a couple of mouseclicks you have a window up and running and a drag and drop designer that is very good. (And it is cross-platform)
Now if you want windows only applications, it is my opinion that C# is the name of the game when it comes to GUI applications, which coincidentally also has a very user friendly GUI designer in Visual C# Express (which is also free).
