lyrically Nas or Mos Def.
But Nas is too monotone and and neither are versatile, ranged or charismatic enough to be called a 2nd best as a whole. Then you have rappers which have a lot more character but don't have the lyricism.
Overall I think you'd have to say somebody like Andre 3k purely due to his marriage of all elements. But nobody blends the elements close to as well as Em.












