Layer visibility shortcut in Photoshop

There isn't a shortcut bound to this action by default; but if you go to the Keyboard Shortcuts configuration (Edit > Keyboard Shortcuts) under 'Layers' there is a 'Hide Layers' option where you can bind your own shortcut.

Mac = command + , toggles selected layer visibility
Mac = command + option + , turns all layers' visibility on regardless of layer selection.

PC = ctl + ,
PC = ctl + alt + ,

I don't think Photoshop has a default hotkey for showing/hiding a certain layer. You can, however, create your own action to do this, and just bind it to a key.

I have software "photoshop assistant". It can bind any key to show/hide a particular layer...and other cool stuff too. You can check it. I tried creating an action, it works but you have to bind choose the shortcut key from the F(x) keys and what is worse, you should choose two different keys for "hide" and for "show layer". It's boring...