How do I configure a Smart Playlist to show songs not in other Playlists?
It turns out that the screenshot, or at least the correct version, is sufficient:



No doubt in part to my tens of thousands of songs, and only a few hundreds currently classified, the playlist took sometime to populate. After reading Kyle's comment, I looked at the playlist and nearly my whole library is now present.

So the answer to this problem can only logically be:

Patience