The 10.4.3 Update delivers overall improved reliability and compatibility for Mac OS X v10.4 and is recommended for all users.

It includes fixes for:

- AFP, SMB/CIFS, NFS and FTP network file services
- AirPort and Bluetooth wireless access
- Core Graphics, Core Audio, Core Image, and RAW camera support
- disc recording when creating and burning media
- .Mac sync services
- Spotlight indexing and searching
- Dashboard widgets: Dictionary, Flight Tracker, Stickies, and Unit Converter
- Address Book, AppleScript, Automator, Dictionary, Font Book, iCal, iSync, Mail, and Safari applications
- Disk Utility, Keychain Access, Migration Assistant, and Software Update
- compatibility with third party applications and devices
- previous standalone security updates

For detailed information on this Update, please visit this website: http://www.info.apple.com/kbnum/n301984

For detailed information on Security Updates, please visit this website: http://www.info.apple.com/kbnum/n61798

The coolest update has to be Disk Utility: With Mac OS X 10.4.3 or later, Disk Utility can verify your computer’s startup disk (volume) without requiring you to start up from another volume. This feature is called “Live Verification.” If Disk Utility discovers any issues that require a repair, you will need to start up from your Mac OS X Tiger DVD or CD and use Disk Utility on that disc to make repairs. (You can’t repair your startup volume while your computer is started up from it.)