An MC isn't great by just or even how many records they sell. Some people do in fact fail to see talent.
Biggie's not the 'best'. He's just one of the popular guys that companies could sell.
U gotta put Will Smith in because look at how diverse his music and career has been. His style of the late 80s, early 90s, late 90s, and in 2002 2005.
NaS, actually can be argued. But in general, U could put him there. Maybe or maybe not top 5. But definately Top 10. Whether U agree wit all he's done in his career or not.
2pac's in darn near everybody's Top 5 or 10. Saying Tupac is better than like Will Smith is like saying Huey Newton is better than Dr. Suess. Both are doing things different but somewaht similar success. I guess that's a good way to put it. We say Tupac as more than just a rapper, cuz that wasn't all he was doing. Rap was just part of it.
Look at Jay-Z and 50 Cent. "I'm only rappin and I'm so great, but wait, the money isn't rollin in. It ain't enuff for me, so I want more." Hence the clothing line, alcoholic products, etc.
The people that started Hip Hop. They're automatically put in all-time. Cuz Hip-hop is still around and not everyone recognizes them like they should.