Comment 3 for bug 1073883

This problem affects me as well, although my settings sometimes survived a reboot. As I can reproduce this, I'd be happy to provide any more debug information if needed.

For now, here's a workaround (if you use GNOME):
* Open 'System Settings'
* Open the 'Keyboard' settings tile
* Click the 'Shortcuts' tab
* Click the '+' button at the bottom of the list, and add as many shortcuts as you want.
(this has the bonus of working even when Unity crashes, so you can set up a shortcut to run 'unity --replace' to get back)