The Notification Center in Mountain Lion can be a life saver or, for some, it can be an annoyance. For those who need to, this TMO Quick Tip explains how to kill it for good.
Previously, Melissa Holt explained how to disable the Notification Center temporarily, in several different ways. She also noted that if you connect a projector to your Mac, notifications are automatically disabled. But not killed for good.
The N.C. icon is circled in red.
Turn OFF Notification Center Permanently
Here's the best way to permanently kill the Notification Center. Open the terminal and type:
launchctl unload -w /System/Library/LaunchAgents/com.apple.notificationcenterui.plist
The Notification Center icon will disappear from the Menu bar at the top. There will be a visible gap, but the system will close it up the next time you click the mouse. Notification Center has been terminated.
Turn ON Notification Center
If you ever need to turn it back on, enter this command in the terminal.
launchctl load -w /System/Library/LaunchAgents/com.apple.notificationcenterui.plist
Then, navigate to /System/Library/CoreServices in the Finder and double-click on the "Notification Center.app" to start it running.
Navigate to /System/Library/CoreServices. Double-click the highlighted app.
The Menu bar icon, in my testing, didn't go back to the far right, but that may be due to the nature of the calendar/time app I have running there. "MenuCalendarClock."
Finally, Apple has a document on Notification Center Basics if you want to learn more.