Perhaps this will damage my hacker credibility, but I use KDE's Kate Editor as my development environment. For a while I used KDevelop, but then I realized the only features I was using were Kate's (note to KDevelop developers: having to decide on a location and filename immediately when I hit New File is extremely annoying. Give me an Untitled!)

The included python.xml (the file that tells Kate how to categorize tokens for highlighting) is a bit insufficient for Python programmers: no differentiation of class definitions, function definitions, or decorators. I've added these and some other minor improvements to my own python.xml and packaged it up with a custom color scheme in kate_colors.tar.gz. If you extract this to your home directory, it will replace a few Kate-specific files. Your configuration options will be kept, but I think any custom colors you've set will be replaced (Kate lacks a way to split these up to make sharing easy). If you select "exogen - Dark" as the default schema in Fonts & Colors, your HTML, CSS, JavaScript, and Python files will look pretty:

kate_colors.png

Of course, you don't have to use the included schema. The enhanced syntax highlighter is the biggest improvement, giving you several more contexts under Text Highlighting Styles.

kate_styles.png

I shared these changes with Adrian Holovaty at PyCon, who I noticed also uses Kate. I guess he couldn't get used to the high contrast color scheme, but here's hoping the new syntax file is serving him well. ;)

(I also recommend the Tab Bar Extension, the Word Completion Plugin, and learning to use those double arrows in the Filesystem Browser panel.)