I agree with hockeyman..Pac and Biggie are over-rated. Nas is a great rapper, and he's definitely part of the top 5 rappers of all time, no question about it.
If you like songs with sexual mind set. check this one its cool: Tupac ft lisa " left eye " lopes: If you really want it. hottt song.
Nas is preety good, I wouldn't put him in my top 5 tho. And Hip Hop is Dead really sucked as an album compared to what I'd expect from him