Nowadays (Feb 2017), the choice is absolutely clear to me - Python 3. Django fully supports it since 1.6 and, moreover, Django 2.0 will be Python3.5+ only.
To check whether your dependency supports Python-3.x or not, use Can I use Python 3? service. Also, check Django Packages directory of reusable Django apps - besides other features there is an indication whether a package supports 3.x or not.
Also, there were a lot of topics about the subject:
- What Python version should I use with Django?
- New project: Python 2 or Python 3?
- python 2.x or 3.x
Old Answer:
This is basically a question whether to choose Python-2.x or Python-3.x.
Should I use Python 2 or Python 3 for my development activity? article in Python docs says:
Which version should I use?
Which version you ought to use is mostly dependent on what you want to
get done.
Since you don't know your requirements yet - then, just to be safe, better stick to 2.x branch. Currently, it has a lot more batteries for all sort of tasks, and not all of them migrated to Python-3.x. Note that it is important to stick with the latest release, in case of 2.x branch - currently, it would be Python 2.7.7.
