for hiphop reference..
Dre-chronic 2001
2pac-All eyes on me
Ja rule(non't like him much but he always has a good quality)
DMX, old scareface, Nas, Fugees, some mobb deep ETC
these days i producer more R&B so i a/b my mixes to:
Jodeci (Cry for you,Freakin you,If you believe in love)
Faith (Soon as i get home, i love you)
Destineys child (dangerously in love)
Total (can't you see)

Ashanti (Baby)
Jagged edge (to many songs to name)
Alicia Keys (the hole album)
other artist like Aaliyah, city high, Mary J, usher, r.kelly, 112 ETC...
when i A/b my mixes these are the main album i compare... most of them were produced very well...
for down south tracks-most these songs weren't produced very well they just get the clubs crunk down here in atlanta, some were produced well
Pastor troy
Lil Jon
T.I
Archie
Baby D
UGK
8ball & MJG
Outkast