I just had to make this list and put it somewhere, to keep track of everything.
The AW book is not even officially in print yet and we already have:
Dead Weight (Daniel Solis & John Harper) - Left 4 Dead + Mirror's Edge, zombie apocalypse parkour
Knife & Candle (Vincent Baker & John Harper) - Echo Bazaar (underground urban fantasy London)
Dragon Killer (Vincent Baker) - celtic fantasy
Rogue Trader Apocalypse (John P.D. Ryan) - Rouge Trader via AW rules
Apocalypse D&D (Tony Dowler) - oD&D hack
Dungeon World (Ben Wray) - another D&D hack
Bulwark (Nathan Orlando Wilson) - surrealist gritty fantasypunk
Sagas of the Icelanders (me, myself and I) - 10th century viking Iceland
AW: Dark Sun (Michael Pfaff) - Dark Sun via AW
Exodus (Robert Bohl) - Battlestar Galactica hack
Vanguard (Matt Wilson) - spaceship sci-fi hack
Gravitas (Bryn Boese and Sean Byrd) - space opera hack
The Many Students of Master Luo Chen (Bret Gillan) - kung fu hack
Bargain Town (Willow Palecek) - "barf forth retail hell"
Age of Sorrows: AW (Kenny Crowe) - Exalted hack
There are at least five more I haven't mentioned. If this list doesn't tell you anything about the impact of Apocalypse World, nothing will.