Turn Off Filename Extension Warning
In Leopard, Apple fixed an annoying aspect of working with the Finder in Tiger. Previously, if you changed a file's extension, the Finder prompted for confirmation. But since no one has ever accidentally changed a filename extension, Apple thankfully added an option to turn that warning off in the Leopard Finder's preferences. Choose Finder > Preferences, and in the Advanced screen, deselect Show Warning Before Changing an Extension.
Safari 5.1.10 for Snow Leopard
Set up short abbreviations which expand to larger bits of text,
such as "Tx" for "TextExpander". With the new custom keyboard,
you can expand abbreviations in any app, including Safari and