Snap2HTML
This application takes a "snapshot" of the folder structure on your harddrive and saves it as an HTML file. What's unique about Snap2HTML is that the HTML file uses modern techniques to make it feel like a "real" application, displaying a treeview with folders that you can navigate to view the files contained within. There is also a built in file search and ability to export data as plain text, csv or json. Still, everything is contained in a single HTML file that you can easily store or distribute.
Homepage with examples and binary downloads: http://www.rlvision.com/snap2html
Screenshots
WinForms application for generating the direcotry listings:
The finished HTML app: