On a tangent, did you know that it costs $60/year to get Red Hat Linux updates*? That's about what a copy of Windows XP costs on a new PC - and that includes Windows XP updates for at least 7 years.
I also wonder if Apple provides security updates for obsolete OSes like Mac OS 10.1, or if you have to first upgrade to Jaguar for $129.
* You can of course download them and install them yourself if you're technically proficient - however, this is probably beyond the ken of home users. It definitely fails the Grandma test.