Display Maestro is a Mac program that provides you with a quick way to change your screen resolution. The application comes with easy-to-configure settings, immediately applies the screen resolution changes, and offers you support for multiple monitors.
This utility lives on your Menu Bar from where you can change the current screen resolution for any of the connected monitors. You can also get immediate access to a report showing detailed information regarding the connected displays. This feature might come in handy if you're unsure which screen resolution is the best for your monitor.
Furthermore, besides providing you with screen profiles that are compatible with your monitor, Display Maestro also brings you potentially unsafe resolutions. These profiles are normally hidden from the System Preferences panel.
The only thing I'd change would be to add an option to define global hotkeys for immediately enabling screen resolution profiles. This feature might prove to be of good use if you're working with multiple monitors and you wish to eliminate the need to move your mouse cursor to your Menu Bar every time you need to change screen profiles.
Still, Display Maestro is efficient, easy-to-use, and works 100%. You should give it a try if you're looking for a simple solution to alter screen resolutions.