Apple have just released a huge update to Mac OS X, taking it to version 10.6.5. The update is 680 MB!
The 10.6.5 Update is recommended for all users running Mac OS X Snow Leopard and includes general operating system fixes that enhance the stability, compatibility, and security of your Mac, including fixes that:
• improve reliability with Microsoft Exchange servers
• address performance of some image-processing operations in iPhoto and Aperture
• address stability and performance of graphics applications and games
• resolve a delay between print jobs
• address a printing issue for some HP printers connected to an AirPort Extreme
• resolve an issue when dragging contacts from Address Book to iCal
• address an issue where dragging an item from a stack causes the Dock to not automatically hide
• resolve an issue with Wikipedia information not displaying correctly in Dictionary
• improve performance of MainStage on certain Mac systems
• resolve spacing issues with OpenType fonts
• improve reliability with some Bluetooth braille displays
• resolve a VoiceOver issue when browsing some web sites with Safari 5
For detailed information on this update, please visit this website: http://support.apple.com/kb/HT4250.
For information on the security content of this update, please visit: http://support.apple.com/kb/HT1222.
You can and should update your Mac now.