Apple has released Final Cut Pro X 10.0.7 with a small grab bag of fixes to improve stability and performance. Amongst the tweaks, the update restores the Letterbox effect “Offset” slider, fixes a problem with uploading clips to Vimeo larger than 1 GB in size, and fixes an issue in which an incorrect frame size is used with filters on two adjacent clips with different pixel aspect ratio. It also deals with an issue where some third-party effects caused the app to stop responding during background rendering and another where third-party transitions incorrectly used black instead of source media. ($299.99 new in the Mac App Store, free update, 1.53 GB, release notes)
Mac OS X Zip Expanding Utility
Firefox (and possibly other applications) may ask you what you want to do with .zip archives that you download from the Internet. If you want to expand them with Mac OS X (rather than StuffIt Expander), you may be unsure of which application actually does the job. You're looking for Archive Utility (in Leopard and later) or BOMArchiveHelper (in Tiger). In either case, the application is stored in Hard Drive/System/Library/Core Services/. Don't move it from there, though, or you'll confuse matters.