Steven Lienhard

Is the Admin Bar in the way while designing the site? Enter control-shift-a while logged into the front end of the site to toggle the admin bar on/off. You will see a temporary dialog confirming if the admin bar is on or off. Refresh the page to see the result.
You can enable or disable this feature by user role from the admin under Settings => SBL Admin Bar

SBL Admin Bar

SBL Admin Bar allows you to dynamically turn the Admin Bar on/off using the hotkeys CONTROL-SHIFT-A. Can be enabled and disabled by user role.

Captin Shmit

Configure your own custom hotkey to redirect you to your admin 
login screen from any public page of your blog. You can finally 
get rid of that unsightly “login” link and not have to 
bookmark/type in the login screen URL!

Secret Passage

Configure your own custom hotkey to redirect you to your admin

SBL Admin Bar vs Secret Passage