I use BetterTouchTool to bind apps to shortcut keys (similar to the way Brett Terpstra does). For example, pressing ⌘⌥⌃⇧-X brings up Xcode. Actually I have ⌘⌥⌃⇧ bound to the caps lock key. This way I can press caps lock-X to bring up Xcode. I have my most common apps bound to shortcut keys. I rarely use ⌘-tab now. Much faster.
I used to have the caps lock bound to the control key, but having an app switcher/system key has been much more useful on the Mac.
I wanted to be able to bind the iOS Simulator to a key, but there are several simulators and Xcode versions on machine. Every time I would try to bind a key to the Simulator a different Simulator would pop up. So I created the below AppleScript to bring the Simulator to the foreground.
tell application "System Events" set theProcesses to application processes repeat with theProcess from 1 to count theProcesses set theName to (name of process theProcess) if theName contains "Simulator" then tell process theProcess set the frontmost to true end tell end if end repeat end tell