Wow what a question. Honestly I listen to many rap artists but there is just something about 2pac, his lyrics and his flow and everything else. He seemed to have a lot of knowledge not just rap skills. He seemes pretty educated about alot of issues.
If you are talking about singers hmm...Missy Elliot is pretty good. I mean she can rap, sing,dance, produce etc..I am sure there are alot out there some we haven't discovered yet.