Most of the applications you'll delete are going to be restored the next time there is a software update, and even still it'll only save superficial amount of space. For example, the Mission Control, Launchpad, Dashboard, Time Machine, etc. apps are all less than half a meg, and only serve as links to call upon these features via Dock or Finder.
If you want to make a substantial cut on space without making your mac bulimic, i suggest Monolingual, which deletes unused language support (which is usually around 500 MB to 2 GB) and redundant app binaries.
Most Mac apps are "universal," meaning they support both Intel and (the older) PowerPC processor architectures, by having every application contain a binary compiled for each. If you're running an Intel Mac, monolingual can be used to delete the unused app binaries, saving 1-2 GB
The solution is a bit of a mystery but if you really have /System/Library/CoreServices/Notification Center.app with the space and not /System/Library/CoreServices/NotificationCenter.app you may have to reinstall the OS or restore that entire directory from backup (or another similar Mac OS install).
As to the load on the computer due to the logging - it should be harmless or at worst a minor slowdown. I have Macs with thousands of messages a minute and can barely measure their load running Activity Monitor even when I have several windows up tailing the logs, grepping for patterns to filter out noise like you mention.
You can assure yourself the system is not loaded with the following command:
iostat 15
You can run with the notifications running and the error messages and without and watch for long term problems in terms of CPU usage and disk IO. Airs and other SSD based Macs generally have plenty of horsepower to deal with thousands of messages a second let alone per minute and the system logging infrastructure scales very well, uses little RAM and is miserly with CPU and disk access.
Now, as far as hunting down the culprit - it's going to be a bit of sleuthing unless someone has already slayed this bug by noticing why the space got added in that directory for the app.
I would probably edit the plist file for that process to set the respawn to be 100 or 300 or 600 until you have a handle on the error (and if you don't want to see so many messages). Also, when you have unloaded (or removed) the job from launchd
control, you could manually run the program from the terminal to see if it output any errors on startup that might help you.
launchctl unload /System/Library/LaunchAgents/com.apple.notificationcenterui.plist
/System/Library/CoreServices/NotificationCenter.app/Contents/MacOS/NotificationCenter
You can quit the app by pressing control+c - If it's a permission error, you could test that by running the process as root:
sudo /System/Library/CoreServices/NotificationCenter.app/Contents/MacOS/NotificationCenter
Best Answer
.VolumeIcon.icns is an invisible file which holds the display icon for each attached disk.
If you delete it - not worth it as it's only about 1MB anyway - it will simply be re-created.
As a general rule - if it's invisibleā¦ leave it alone.
BTW, Mac doesn't have a 'file explorer' it has Finder.