Open System Preferences with a keyboard shortcut
Add it as a global shortcut (under All Applications, not System Preferences), and include an ellipsis in the menu name (either ... or ….):



The only apps this method works for are System Preferences, System Information, and App Store. For others, see:


Launch an OS X app with a keyboard shortcut - Super User (instructions for using AppleScripts, a list of third party apps that support application triggers)
OSX show/hide specific app global hotkey? - Super User (instructions for using Automator services)