>I think I would default it to on

I forget now what we're talking about. :) If it's the message to confirm that, through some extraordinary combination of circumstances and pure blind luck, data was actually saved when the user clicked Save, I wouldn't devote a particle of development time to it. That includes designing the message box (and localizing it), the checkbox to turn it off, the registry setting to store that it has indeed been turned off, and the dialog box item that lets you turn the stupid thing back on again. :)

>but present the user with the option of turning it off on the spot. Similar to how [ahem] Microsoft includes a "Do not ask me again" checkbox in their dialogs.

I think this is a great way to handle many of these situations, though. As long as the message tells the user where she can change it, and that this is a reasonably easy thing to remember a month later.