The decision which to learn should be based on what your overall goals are. I am myself starting to learn python and will be moving towards learning Django. I don't see Django as the final solution to everything but its a solid start to being exposed to python and its web frameworks.
I have looked at Flask and Pyramid. Both seem quite good but at this moment I'm looking at learning a framework that will do a lot of heavy lifting for me. Django will do that better. Likely in about a year or more, I will be in a position to decide for myself based on my own experience whether getting into Flask or Pyramid would be a better idea for my projects.
Personally, I'd rather go to a restaurant and see the full buffet and sample the food that way (ie. Django) versus go in and pick niche items of the menu (ie. Flask).