dunno if this forum is aware of this or not. but to me this is a good source for exploring hip hop's history. it's a playlist that was compiled a few years ago. it gives you hip hop music by the year. goes from 1979-2009. i really like the 90's lists. the 2000's look pretty lackluster. but i'm assuming the 1980's lists are pretty decent samples from those years if you enjoy that type of music.i don't really like 80's rap as much if i am being honest so it's hard for me to comment
The Rub ยป History of Hip-Hop