But, you can change it back relatively easily. Simply use the global Keyboard Shortcuts in the Keyboard & Mouse preferences panel, and set up shortcuts for the two menu items in Safari (make sure Safari isn't running first). Click the '+' under the list, select Safari as the Application, type in the exact menu name (in your language), and set the shortcut to the one you prefer. Re-launch Safari and voila!
[robg adds: On US systems, the tab switching shortcut was shift-command and the arrow keys. In experimenting with Safari 1.3, I found it still works ... except on newly-created blank tabs (where the new shortcuts do work). I then went ahead and used the above method to officially change the shortcuts back, and they now work on all tabs again.]

