^Royce? Cmon man he hasn't had a big impact yet. Eyedea? Cmon....no.....in this subject you can't really ask who's was the greatest. Cause there's so many other factors that take hold lik what style? Who has had the biggest impact or what not. But in my opinion:
( )=why I like em.
Tupac (poetic)
Biggie (poetic)
Run-DMC (paved the way)
Rakim (illest lyricists)
Jay-Z (poetic, illest lyricists)
Nas (poetic, illest lyricists)
Dr. Dre (made big things, best producer)
Eminem (illest lyricists)
LL Cool J (poetic, been around fo a minute)

Those that said 50......I think 50 is hot but as far as being the greatest? Hell no! Mystical? Fuuuuuuck no!!! I see Kanye doin big things as we'll as some others.