This has a side-effect that I don't like. Python's virtualenv, once activated, places the string '(venv)' (assuming you named it 'venv') immediately before your prompt to let you know that it is active in this terminal. However, this export hides this modification, and it makes it difficult for me tell whether the venv is active or not.
Personally I do not use virtualenv activation. Instead I prefer to explicitly launch Python and/or scripts with bin/python, bin/scriptname etc., either with my current working directory in the virtualenv, or by creating a symlink ./bin -> .virtualenv/bin in the project root.
