If you're an Aperture 2 user, you'll probably want to summon Software Update or directly download the Aperture 2.0.1 Update that Apple released today. The update addresses performance issues and overall stability while also fixing some other minor issues. Is that vague enough for you? If you're really interested in what has changed, Apple has posted details online.

Apple has also posted a GarageBand update that brings the iLife app to version 4.1.2. Like the Aperture update, this one improves stability but it also addresses issues with the automation of software instrument parameters, FireWire and USB based audio devices and Magic GarageBand--a lot of improvements by the sounds of it.

Updates are available online as well as from Software Update.