The same thing is happening here with udev 0.084-3 and hal 0.5.6-2. Downgrading to udev 0.081-1 and hal 0.5.5.1-5 fixes it (though that combo had another problem: mounted HD volumes not appearing on the desktop or the kicker applet. That issue at least seems to be solved in 0.084/0.5.6) udev 0.084-4 and hal 0.5.6-4 from unstable have the same problem with not displaying a device's mounted status as the packages in testing.