Last night while poking about the web in my typical pseudorandom fashion, I found a new tool which may help prepare for the next time Windows decides not to boot. TestDisk is a tool designed to run under multiple OSes which can perform lots of handy data recovery functions including repairing and restoring an NTFS boot sector.
It turns out it's already available on the System Rescue CD I've been using. I just needed to poke around a bit more.
I'll be making backups of the MBR and boot record since I don't expect this to be the last time that Windows goes belly up. *sigh*