Yea I would have to say my favorite old school group is U.M.C. Their best song being never never land:
YouTube - U.M.C.'s - Never Never Land
Beats insane but the hook gets annoying after a while (im a beat man, its beat first, then lyrics for me) I'm actually astonished at the lyrics of UMC. The made me appreciate lyrics. Since I started listening to rap, around age 11 (now 1

, I was just exposed to southern style dj type beats mixed with atlanta underground rap. Those lyrics really get monotonious.
.UMC's song 'Morals' (awesome beat again) has a verse about my life, so that was another cool thing again.
Wu Tang Clan also is some classic rap that ive been listening too. Method Man and ODB have the voice to rock the beats. The song Gravel Pit is my favorite:
YouTube - Wu Tang Clan - Gravel Pit [2001]
Happy tokin'