I've never seen a Windows system that was broken by an update. (I've heard there have been some bad updates, but I've never known anyone who's encountered problems because of them.) On the other hand, I've seen people keep clicking the button to postpone updates for months or even years; when something goes wrong with their computer, it can take hours of downloading/installing updates to bring it up-to-date to make sure that the problem isn't something that's been fixed already.
For the vast majority of Windows Home users who use their computers for web/email/Word, I think it's great to keep them up-to-date, mandatory. For anyone who's truly concerned about this, I suspect someone will find a registry edit that'll provide the deferred update behavior.