Thinking about this topic and back to one of the first songs that got me into hip hop.

Hardnoise - "Untitled"
http://www.youtube.com/watch?v=tPm2P0kBG08

Probably '94/'95. I was 13/14 and a mate had got me into RATM and Sensor as his older sister was well into them. I prefered less guitary stuff then heard this one day. Still sounds good.

:ETA: Demon Boyz - 'Northside' needs a mention too
http://www.youtube.com/watch?v=aSzzhiotO9A

:ETA2: There's also a early 90s hip hop track that I loved to death that heavily sampled the film 'Aliens' that I can't for the life of me remember what it was called.

This would get my vote

The Fab 5 - Leflaur Leflah Eshkoshka
www.youtube.com/watch?v=i4sW3jJuVDg

6 in the morning by Ice t.

Straight outta compton by NWA.

Freedoms got an Ak by da lynch mob.