Default Folder X 4.6.6
St. Clair Software has released Default Folder X 4.6.6, reassigning the Command-D shortcut to jump to the Desktop rather than invoke the Duplicate command. The Open and Save dialog enhancement utility now enables you to use its Rebound feature (to quickly return to recently used folders) in column view, fixes a bug that caused some apps (like Monosnap) to save files with the wrong file names, and disables audio previews by default to avoid triggering OS X to switch to the high performance graphics processor on some Macs. ($34.95 new, $10 off for TidBITS members, free update, 10.7 MB, release notes, 10.6+)
Thank goodness! The redirection of command+D from "Desktop" to "Duplicate" inadvertently caused me to duplicate huge folders of data. I think I removed them all, but I suspect I didn't (wasting space on my drive).
By reverting command+D to "Desktop," I can once again use my Mac intuitively, quickly, and nicely, returning DefaultFolder X to my most indispensable utility for the Mac.