We've been anticipating the release of Mac OS X 10.6.7 for several weeks, and the update has finally dropped.
As you can see from the notes above, one of the major improvements is to Back to My Mac, which has been seemingly neglected for the last several updates. Mac users in Windows-centric offices will be happy with the SMB file transfer fix, and several Mac App Store bugs have been resolved as well.
The update requires a reboot and, when I got it from Software Update, showed a download size of about 312 MB. The standalone downloads are 475 MB (for the 10.6.6 to 10.6.7 delta updater) or 1.12 GB (for the combo updater valid on any 10.6.x Snow Leopard installation).
As always, it's a good idea to make sure your backups are current and you're not in the middle of any mission-critical work before running a system update -- no harm in waiting a day or two while the first round of upgraders shakes out the issues and gotchas.