The funny thing is to you a classic would be "C.R.E.A.M". If you have half a brain you can tell the song's about money before you even press play. What does Lil Wayne rap about? Usually money, power, influence, etc. In all honesty, they're rapping about the same things with a difference in the amount of vocabulary. What does Nas rap about? Power, family, his home town, distaste with other rappers abilities including Jay-Z who is currently going at it with none other than Lil Wayne. I'm not saying they're identical because they're not (They both have completely different styles), but when it all comes down to it, they're subjects can be very similar.
Oh and by the way, a classic is a song a lot of people enjoy and still listen to numerous times years after it comes out. "Go DJ' came out in 2004...