In iTunes 11.1, I noticed that if I press the ⌥ / Alt / Option key then the back button on iTunes becomes a Genius shortcut.

I use Genius a lot so I think that’s cool.

 

The Genius icon will stay in place until you Pause / Play. Nice way of reminding you that you are in Genius mode.

Without the ⌥ key pressed, just in case you forgot.