If I print my system python's `sys.path` on ubuntu, I also get paths like `/usr/local/lib/python2.7/dist-packages/setuptools-0.8-py2.7.egg` and `/usr/lib/python2.7/dist-packages/PIL`.

I fear it is a bit ubuntu-specific to have a site-packages/dist-packages split, but for ubuntu's case you also have to exclude `dist-packages` from `x`.