What are the bare minimum libraries I need to install to use PySide?

[wysota]

We just need to be able to create all the standard GUI widgets and an OpenGL canvas.

So you need QtCore, QtGui and QtOpenGl plus image plugins if you want to handle other formats than png.

There's simply no way I can believe that it's necessary to fill up that much space with temporary files.

Believe it or not but that's the truth. QtWebKit is the one taking most space. And you're probably building them in both debug and release modes.

Why don't you just install a binary bundle instead of compiling Qt on your own?