Like most topics on here this is relative, that said here are some nominations:

Salt-n-Pepa - "Push It"
The Fat Boys - "Wipeout"
As a 7 year old living in rural New York these songs were some of the first hip hop played on the radio there, it sounded so different from anything else being played at the time. These songs planted the seed for my love of hip hop.


Dr. Dre - "Nuthin But A G Thang"
This was the first time I heard Snoop, his flow and voice stood out. The way Dre re-recorded the Parliament samples used on The Chronic gave him a lot more flexibility in flipping those samples in new ways. This production method would go on to be widely used by many producers.


Wu-Tang - "Protect Ya Neck"
Just like Dre, RZA had a unique production style which proved influential and at the time sounded different from everyone else. The whole squad was grimey and gutter in comparison to everyone else on the radio: Native Tongues, LL, Kris Kross. Plus, after Wu came out how many assembled squads tried to get in the music industry using their template: put out a group album and then solos for everyone.