umm... no. Microsoft Fixes security holes in windows.
they DON'T fix security holes in other applications.
Oh, and the update is free. when apple fixes it, you have to buy a completely new version of the OS. And of course, since apple doesn't give a flying penguin wether older apps work, you need to get all new programs too. oddly, everybody in this instance rightly looks at the program vendor, and not Apple as the cause. And yet the same scenario after a windows upgrade and the stare goes straight at windows and MS.
BC Programmer is right that Microsoft does fix their own security holes, just not ones in 3rd party apps (just like apple).
However, BC Programmer is wrong when saying that you need to buy a completely new version of the OS when apple fixes it.
When apple releases an OS, you automatically get free updates for that OS until updates are no longer made for it (they still make updates to OS 10.4, for instance, and that came out in April of 2005).
Also, the needing to buy new software when a new version of the OS comes out is not completely true for mac or for windows. In both cases Microsoft and Apple try their best to make everything in the new OS work with everything that worked with the old OS (testing of major software applications, sending dev kits to all developers, etc.). However, if there is some new jump (like Mac's jump to intel processors and OS, or Microsoft's jump from XP to Vista or 7), the 3rd party companies simply have to make updates to their applications in order for them to work.
To alleviate these issues, both companies give out the dev kits to all developers as far ahead of time as they can (and often this isn't far enough in advance).