Deprecate monkey-patched site.py
easy_install overwrites site.py when installing eggs, to tweak path resolution order slightly. distribute also (by historical accident) ships the patched site.py, and as a result it can replace the original site.py, depending on which site.py is imported first.
Reinstating http://mail.python.org/pipermail/python-checkins/2006-April/051329.html would make things more predictable (only one site.py is in use, although it may or may not be the rewritten one, depending if the easy_install command was used to install a package).
Deprecating site.py rewriting entirely would be better, because it will prevent an easy_install hack from unpredictably changing the semantics of its successor, or from interfering with new features in the Python distribution's site.py.