I use TextMate for all my Python programming needs. It's not an IDE per se, but it does a lot of stuff that an IDE does (without all the cruft of an IDE). It has syntax highlighting, code folding, integration with various SCMs through the use of additional bundles (I know it supports SVN, Git, Mercurial, Darcs, and probably a few others). It's also quite extensible and customizable (again, through the use of bundles). It also has a basic concept of projects. One place where it doesn't shine, though, is in code completion; some bundles have limited support for code completion, but it's generally not as amazing as that of most language-specific IDEs. Given how awesome TextMate is, though, I don't know sacrificing that. TextMate's definitely made me much more productive.