With rap you have to go to patient zero. It makes no more sense to note NWA for creating gangsta rap than it does to note Public Enemy for creating the protest rap that became gangsta rap. It makes no more sense to credit Public Enemy for creating protest rap than it does to note The Fugees for commercializing rap and turning it into white guy music.

Patient Zero is the Sugar Hill Gang. Sugar Hill gives you Run DMC which gives you Public Enemy which gives you NWA which gives you the Dre constellation which gives you the Wyclef constellation which gives you all the shit we have today.

Back up on Sugar Hill and you're squarely in the realm of disco. There's no good spot to stop because you can trace a line from disco back through surf rock back to Elvis back to jazz and straight through negro spirituals. So you pretty much have to put it at the innovation of the Sugar Hill Gang - rapping.

Jeron Lanier argued that rap was the last evolution in popular music, and that everything that came after is just an iteration on a theme. You can point to a few songs and say "that's where rock'n'roll started" and you can point to a few songs and say "that's where jazz started" but rap started with one song by one band.

On the flip side, the Amen Break essentially defined electronic music from 1987 to 2008. I'd give it runner-up status simply because the vehicle for that definition wasn't a Winstons album, but Zero G Datafile 1.

People don't really understand how ubiquitous that sample was, how many places you could get it, and how many places it showed up.