I was thinking about it from time to time. The list would welcome a bit of an update or, better yet, a second installment regarding post-2003 wads (a lot has changed since then). What would I add? Brutal Doom is a pretty obvious one, lilith.pk3 for the drama surrounding it, UAC Military Nightmare for spawning Terry wads. Maybe Plutonia 3: Return to Surface for trying to create a sequel to one of the most revered mapsets of all time without required experience and completely falling on their face.
I'd like to see what others think, it's indeed an interesting subject.