I love Trac as a project tool - and I'm quite satisfied with Subversion for version control (or, more recently, with SVK as a version control tool based on Subversion). But darcs has also excited me because it's so beautifully bureaucratic - and now there's also Trac on Darcs - a patched version that works with darcs instead of Subversion. I think I'll take a closer look at that ...
The same patch also allows a Bazaar-NG backend for Trac - which is particularly interesting because both Trac and Bazaar-NG are written in Python. I think I should take a look at that part as well.
And just now I was pointed out in IRC that SCons is also Python - a pretty nice replacement for the already quite old Make.
This all sounds almost like Developer Nirvana.