The latest build of OS X Leopard ( 10.5.5 ) is now available for download or via Software Update. The update includes a whole raft of fixes and improvements and so far there is little noise about possible problems caused by this version.

There are a couple of comments on this Digg thread suggesting that the update may cause problems with iChat and Time Machine, but at the time of writing these appear to be unconfirmed and may be local issues with the users reporting them rather than a widespread issue.