Just a note, pandoc (implemented in Haskell) makes it almost a joy to work with various "dialects" of ReST/AsciiDoc/Markdown etc. It feels like what python's ReST should have been (at least the last time I looked, it was pretty hard to get different html out of it - even if it is supposed to be extendible). If you have a dependency on python, staying with the python libs are probably best, but if you just want "a document system", I recommend having a look at pandoc.
Actually, i am using sphinx and latexpdf to generate project documentation and it is more then awesome to generate beautiful looking LaTeX documents with graphiz graphs in high-res but only writing rst... :)
