Robust and simple GUI toolkit for Python to start with

Question

What GUI Python toolkit would you recommend to start with when switching from console-based scripts to something more user-friendly? For example, a framework/toolkit for creating a program with graphical input and output (something like a sketchpad), which is also cross-platform and free and open-source?

Answer 1

A popular choice is Tkinter. But there is also a recently released framework named "Kivy".