Apple have just released Aperture 1.1.1, a free update for current owners of Aperture. This update addresses several issues related to performance, stability, color correction, and display compatibility and is recommended for all Aperture users.

Note: You must first update to Aperture 1.1 and Mac OS X 10.4.6 or later before installing Aperture 1.1.1.

Website: Apple Aperture 1.1.1 Update