Apple has released MacBook Air and MacBook Pro Update 1.0 for the models introduced in June 2012: both 13- and 15-inch sizes of the MacBook Pro, the MacBook Pro with Retina Display, and both the 11- and 13-inch versions of the MacBook Air. The minimal release notes say that this release “fixes an issue that can lead to increased CPU power consumption, and it improves compatibility with some USB devices.” Requiring Mac OS X 10.7.4 Lion, the update should appear in Software Update for affected models, or you can download it directly from Apple’s Web site. (Free, 76.64 MB)
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.