Recently, Apple quietly added the Safari browser to its automatic update program. If you simply un-check it, the update reminder will come back until you’ve installed it (or gone crazy). Here’s how to get rid of it permanently.
When you see the Apple update screen, un-select everything except Safari. Then go into the “Tools” menu and select “Ignore Selected Updates”. (Note that it’s easy to get this backwards and select everything but Safari, which will not work—you need to select only Safari.)