is my dbus setup broken? (or: why aren't the envvars set?)

Question

Lots of dbus-using applications respond to method calls and send signals just fine, so obviously not everything is broken for me. However:

1. In my terminals, $DBUS_SESSION_BUS_FOO environment variables are never set automatically; I have to either run eval $(dbus-launch) or eval the contents of ~/.dbus/session-bus/[machine-id]. This also affects some but not all programmatic interfaces to dbus—python-dbus can connect to the session bus just fine, but dbus-core running under Haskell needs to set up the environment variables for itself.
2. Some applications do not work right; e.g., audacious doesn't send signals (running it with --verbose reveals that it gets passed NULL instead of a proxy).

I've tried launching fluxbox using dbus-launch, as suggested in dbus-launch's man page, but that doesn't affect anything. Is there some simple config thing missing?