Check out some of those 4 I mentioned. Chali 2na was actually part of Jurassic 5, which you may recognize. I got into hip hop big time in college so I had alot of friends who knew all these underground artists and I just followed the ones I liked.With Jay-Z I recommend listening to Coming of Age on the Reasonable Doubt album and Coming of Age (Da Sequel) on the Hard Knock Life album... those were the days when he was really good... you listen to his stuff now and it doesn't even compare.. and with Nas I recommend I Gave You Power from the It was Written album... should be able to find those on Youtube.
Yeah, I'm not really up to date on the lesser known artists.. so not sure who most of them are.
Oh and Lyrics Born - I forgot him the first time.