Early hip-hop best songs are
Big Daddy Kane-Ain't no half-steppin
KRS-One-Brigde is over
Eric B and Rakim-Make em clap to this(occording to The Source, which isn't saying much-the best beat of all time)
Run DMC-Beats to the Ryme-most magazines say that King of Rock is their best but i disagree.
obviously there are others but thats a good crew from early era.
after that-and separate from those would be
Nas-Anything off the album Illmatic-"World is yours" might be best song
Jay-Z-Dead Presidents
Biggie-take your pick-I'd go with Unbelievable or the Warning
Big L-Ebonics
GZA-Shadowboxing
Raekwon-Incarcerated scarefaces
Dre-all of the Chronic
Company Flow-bad touch example