Aside from dropping the dependency on Glade (and our custom glade.py) there is room left for GtkBuilder goodness. A bunch of UI code is made into the Python source code, which is not good for several reasons:

   - Glade+GtkBuilder offer a visual way to layout and configure everyting. Less code, better UI/source separation, easier contribution, etc.
   - GtkBuilder also wraps the different enums and constants of Gtk we use in our code, like GTK_FILL or GTK_STOCK_DIALOG_WARNING and things like that. This is not accessed the same way in PyGTK and PyGObject (Gtk.AttachOptions.FILL for example). Thus, putting all that in GtkBuilder files makes it easier to port to PyGOBject (and to other languages in theory).

So once Thibault merges his GtkBuilder branch (which drops the Glade dependency), it would be nice to track every not-custom UI code in the source, and port this to a proper GtkBuilder file. This is an easy but laborious task, see the PreferencesDialog example (in the bug dependency) to see how it works.