I posted awhile ago about my recommendation for an IDE (Wingware's IDE). I'd like to retract that recommendation in favor of one I've been experimenting with lately: Eclipse + pyDev. First off, the IDE is open source and is one of the most popular IDEs on the market today. I wasn't aware of how Aptana had fully integrated Python as a plugin until yesterday. I can only say that I am extremely pleased with the result. They did it right, no doubt about it. Check it out on your favorite OS today. For Ubuntu 10.04 users, simply add Eclipse to your system through the Software Center and then follow the instructions on pydev.org to add it as a plugin. Make sure you follow the instructions for adding it as a plugin.