I found a way to create a list of your MP3s:

1. You need the Send To Extensions for Windows, a Microsoft enhancement to the right-click menu. Go here (http://www.ise.ufl.edu/kisko/files/freeware/Powertoy%20-%20Win95%20tools%20from%20Microsoft) and download the files sendtox.dll and sendtox.inf to your desktop.
2. Right-click sendtox.inf and hit Install.
3. Go to your MP3 folder and hit Ctrl-A to select all your music files, then right-click and "Send To --> Clipboard As Name" - this stores the filenames of all your MP3s on the clipboard.
4. Create a new .txt file and paste the clipboard contents into it. That's it - pretty straightforward!

One caveat - any subfolders in your MP3 directory will simply be included as a folder name; the command will not probe them for their individual MP3 files. Still, it's quite useful if you have a naming scheme like mine, where there are hundreds of individual tracks in the root directory, but also a collection of albums, each with its own folder. You could always repeat the command inside your subfolders and add those contents to the list.

Thanks to Madkatz and clintb for their alternate methods (below) -if anyone else has one, this is clearly the thread :)