Ghostface Killah. The guys not even my favourite but his dominance is undeniable. Not only does he have the best solo stuff, which in my a opinion is huge when your'e figuring who the best MC is, but he regularly contributes to other people's albums and steals the show.
He's versatile, unique , can speak on a number of different topics, and he ALWAYS comes out strong. Whens the last 'wack' ghostface verse you heard ? When have you heard him come on a track sounding like he was tired or just not into it? Ghost brings it everytime without being too repetive.