PyCharm 3
The intelligent Python IDE with unique code assistance and analysis, for productive Python development on all levels.
Free Community Edition
for pure Python coding and learning
Intelligent Editor, with code completion, on-the-fly error highlighting, auto-fixes, etc.
Automated code refactorings and rich navigation capabilities
Integrated debugger and unit testing support
Native VCS integrations
Customizable UI and key-bindings, with VIM
emulation available
And much more, all available under the Apache 2 license
http://www.jetbrains.com/pycharm/
103 mb !!