From there I followed the advice on How to fix your Hard Drive When Vista Won't Boot and found a couple of variations of my intelide.sys file in my DriverStore. I dutifully copied each one to my /system32/drivers folder but in each case I was either left with the original behavior or Windows would start to boot and then Blue Screen Of Death on me.

However, I was able to access the whole disk (no hardware failure - just Vista stupidity) as well as connected USB drives. So for the last 12 hours or so I've been using robocopy to back up the machine just to be sure (I have a backup from not too long ago as well but I don't like the possibility of losing stuff forever), and then I'll spend the next 2 days or so reinstalling Windows and my plethora of applications. This would be quicker except robocopy keeps getting confused and going down infinite folder trees like /AppData/AppData/AppData... and finding Access Denied on certain files.