Top 10

Rappers (not in order)

Nas
50
Game
Fabolous
Young Jeezy
Kendrick Lemar
Raekwon
Pusha T
T.I
Prodogy

Producers

Timbo
Dre
Just Blaze
Sha Money XL
Swiss Beats
Kanye West (better producer than rapper)
Justice League
Farmboy (of course)
Alchamist
R kelly

R&B Male

R Kelly
Joe
Donell Jones
Chris brown
Maxwell
Usher
Jodeci
Bobby Valentino
Ron Isley
Jon B

R&B Female

Mary J
Brandy
Monica
Aaliyah
Faith Evans
Ciara
Bridget Kelly
Keri Hilson
Kesha Cole
Sparkle

Just a little taste of what i like, if you disagree you can do your own list.