This tidbit is buried in another thread, so I'm highlighting it here:
Running the OS X 10.6.8 Combo overwrites Safari 5.1 with Safari 5.0.5 (and, for some unknown reason, Software Update doesn't pick up on the fact), so if you('ve) run the Combo for troubleshooting purposes you need to d/l and install
the v 5.1 standalone to get current (if you haven't already done so).
(Opening the Combo in Pacifist apparently shows that Safari 5.0.5 is a component of the OS X 10.6
.8 Delta.)
You can check your current version of Safari at Safari > menu bar > Safari > About Safari.