I suspect many will balk at its $7.99 price, but if you use a Mac and your line of work has you constantly switching your screen resolution, EasyRes may be a worthwhile investment.
The app installs a small icon in your Mac's menu bar. From this icon, you can quickly and easily change the screen resolution for any connected display. It saves a bit of time from accessing display settings in System Preferences.
Click on the EasyRes icon in your menu bar and you'll see your available resolution options, along with any recently used resolutions. For Retina displays, the app splits the resolutions into Retina and standard lists. Click on the Edit option below the list of resolutions to add a nickname for some of your more commonly used settings. Lastly, in the app's preferences, you can adjust the number of recently used resolutions that show up in the list.
Next to the lists of resolutions, EasyRes provides a small window with a live, animated preview, giving you a glimpse of what a resolution will look like as you hover over a selection. On my MacBook Pro running Mac OS X 10.8.4, however, this preview was neither live nor animated. It failed to show any open windows and showed only my empty desktop.
Update: The cause of the preview window not showing open windows turned out to be the auto-hiding setting for my Dock. With auto-hiding disabled, the preview window works as advertised. The developer is working on an update that will allow the preview window to function fully no matter your Dock's settings.
(Via One Thing Well)