After spending a few hours (OK, more than a few) tracking down why my USB drives weren't automatically being mounted by nautilus I eventually tried a clean install. This didn't fix it. However, when I compared my Maverick VM and my Maverick laptop the main difference was the presence of a USB mouse and keyboard that had been plugged in since the install.

I unplugged them, and everything that didn't work now worked (Disk Utility aka palimpsest). After a reboot automounting also worked again.

For more, see here:
https://bugs.launchpad.net/ubuntu/+s...fs/+bug/435136