Fast and easy GUI prototyping with Python

[erokar at gmail.com]

Which tools would you use? I want the interface design to be as easy
and fast as possible, all ideology aside. I'm considering either
IronPython+Visual Studio or Python+Qt -- but I'm open for other
suggestions.

Visual Studio seems to offer the easiest solution, but is IronPython
stable enough? How easy is the IronPython/Visual Studi integration?
What about IronPython Studio?