I recommend the Enthought Python Distribution, available here. From the EPD homepage:
The Enthought Python Distribution provides scientists with a comprehensive set of tools to perform rigorous data analysis and visualization. Python, distinguished by its flexibility, coherence, and ease-of-use, is rapidly becoming the programming language of choice for researchers worldwide. EPD extends this capacity with a powerful collection of Python libraries to enable interactive technical computing and cross-platform rapid application development.
There are free and academic versions.