It depends what kind of rap… Beastie Boys & Run DMC are good kinds of rap.
Also,
A Tribe Called Quest
DJ Format & Abdominal
Binary Star
Blackalicious
Boogie Down Productions/KRS One
Chali 2na
Del the Funky Homosapien (first 4 albums)
Deltron 3030 (first album)
Dilated Peoples
DJ Jazzy Jeff & The Fresh Prince (first 3 albums)
DJ Shadow
Eric B. & Rakim (Paid in Full)
Gang Starr (Step in the Arena)
Guru’s Jazzmatazz
Hieroglyphics
Jurassic 5
Kool Keith (not for everybody)
Lyrics Born
Mighty Underdogs
Mos Def
People Under the Stairs
Quannum
Ugly Duckling
Ultramagnetic MCs
Wu-Tang Clan