I've managed to get them back without nuking the thing and starting over. I just happened to need to download and save something off the web to burn to a CD before I nuked the thing and that's what enabled me to find the folders and get them back. The folder Firefox is set to save things to just happened to be in my Users folder, and I didn't change it before I saved the file.
After I saved it, I was able to find the file using search, from there, I was able to reset the preferences to make the files and folders visible.
