Are we talking about real rappers, or making up our own rapper persona?
If option A, I guess for me it'd be Toby Mac, because he's clean, creative, and (unlike 99% of rappers) can sing, too. He's not the greatest singer by a long shot, but he does a decent enough job to where I don't mind listening to him.
If option B, I'm not sure on a name for myself, but it'd have to reflect my nerdy nature, especially since the last song of any sort that I've written was a commical tribute to Tomb Raider.