Mac OS X Leopard was one of the most significant updates to Mac OS X, with over 300 new features. Some of the most notable additions include Time Machine (an automated backup solution), Spaces (a virtual desktop environment), and Quick Look (a feature that allows many file types to be viewed directly in the Finder by pressing space bar. Leopard was also the first version of Mac OS X to include Boot Camp, a feature that allows you to run Windows on your Mac.
Besides the above features, Leopard also provided several enhancements to existing Mac OS X software. For example, RSS feed support was added to Mail, advanced photo filters were added to Photo Booth, and the Spotlight search feature added support for boolean operators. Leopard also shipped with Safari 3, the third major release of Apple's web browser.
The final Leopard software update was 10.5.8, released on August 5, 2009.
Updated: October 24, 2012