If you don't mind committing to Anaconda Python distributions, then you should simply use conda. You can still pip-install things within a conda environment, a

If you don't mind committing to Anaconda Python distributions, then you should simply use conda. You can still pip-install things within a conda environment, and conda can manage more dependencies than just Python dependencies (a common use case is managing R dependencies for a Python statistical workflow). You can do conda list -e > requirements.txt then conda create -n newenv --file requirements.txt to create a Python environment from the frozen requirements. I believe that conda makes it easier to selectively update, but even if you don't enjoy those features of conda, the same two-file trick as in this post will work for conda as well, since you can use `conda update --file ...`. Conda's "dry-run" features are more useful than pip's as well. The perfect feature for conda to add is the ability to specify alternative Python distributions, either by a path to the executable, or by allowing alternative Python distributions to be hosted on Binstar. I can understand why Continuum wants conda to heavily influence everyone to use only Anaconda, but I think the goodwill of making conda work for any Python distribution would bring more to them than keeping it focused solely on Anaconda. (For example, I know some production environments that still use Python 2.6 and are prevented from updating to 2.7 -- and even if they did update, they'd need to keep around some managed environments for 2.6 for testing and legacy verification work).