For me, its Joe Budden. The guy makes 8 minute, 10 minute, 15(most recently) minute songs with some real story and substance. Plus, the wordplay and flow's always fresh. "I just wanted the world to see that I was for real wit it/
Wanted a deal, I got it and couldn't deal wit it..."-All Of Me
Jay an Em for their worldplay, NaS and some other guys (mostly East Coast) for me are contenders, but yeah, looking at the music alone, Joey's it.
So IYO, who's nice on the lyrics tip?