elitism aside, what i mean to say is that this is one of the more subjective questions one could ask. there are quite a few ways to approach this question as well, none of them necessarily better than the other (personal opinions removed). i guess everyone has their favorite emcees and no one is going to convince them that their choices are any better. we can look at abilities based on flow/delivery, linguistic abilities, ingenuity, popularity (i.e. artists in ski movies are always popular and most of the choices are subpar in the whole scheme of things IMO), etc. Choosing five is tough.
Some of my favorites:
Nas (Illmatic era)
Pharoahe Monch (Organized Konfusion)
Have to mention Wu-Tang:
-Gza is certainly the most talented in terms of lyrical abilities, very articulate, complex rhyme schemes, etc.
-Raekwon holds it down with GZA (Only Built 4 Cuban Linx and Liquid Swords are two of my favorite albums)
Kool Keith in terms of ingenuity (he is one of the most innovative, perverse acts out there, never signed to a major label, invented genres of rap, see: pornocore, etc)
Recommended albums: Sex Style, Masters of Illusion (Kutmasta Kurt)
Big Daddy Kane (mastered hip-hop on so many levels-flow, complexity, linguistics, rhyme scheme, he can spit flawless rhymes for literally 5 minutes straight, and is one of the most heavily sampled emcees out there-practically every act through the 90s bows down to him)
Kool G. Rap (check out the album "4,5,6") specifically the track "take em' to war", he used to rap with mf grimm and all of the verses on that song are fucking amazing. extremely violent, graphic, gritty style)
Breezely Brewin' (just uploaded "Clear Blue Skies" to media and arts, definitely check that out, very accomplished flows, rhymes, etc., and no one knows this dude, so slept on)
A.G. (as in Showbiz and A.G., check out "Runaway Slave" and "Goodfellas" I just love the guy's flow and tone of voice. production from showbiz is flawless as always. The second album is a lot more gritty.)
There are so many other emcees we could get into here. These are my suggestions. People will
disagree with me for sure, and that's fine. Remember this is all subjective, so i guess there is no definitive "correct" answer, as is true of most things in life.
My preferences all lean toward the early to mid/late 90s. That was my favorite and i believe most consistent times for hip-hop. Emcees were not making music unless they were very talented. Even some of the shittiest hip-hop coming out of that period, blows away anything today based on the afforementioned categories. I am not a big fan of Vinnie Paz because I hate his delivery, he has absolutely no flow, he's just a fat, untalented fuck. The production for Jedi is dope (thanks to stoupe); I just wish he could find a better emcee to rap over his tracks. Slug was tolerable on "Overcast". He just really can't compare to any of the stuff i mentioned. Very smart guy obviously. I feel he would be better suited to writing poetry or a book. That type of work from him would interest me. I definitely went through a phase where I loved the white emcees and they certainly have talent. I guess they realy can't be compared to these classics though. Buck 65 escapes all of my criticism however.
I leave you with some organized konfusion. "Bring it On" off of the album "Stress: The Extinction Agenda". This is probably my favorite song of all time from my favorite emcee. The guy is absolutely unreal. You have never heard flow like his or even Prince Po's before. These guys sound like they must have studied linguistics because their rhymes are so fucking complex. Monch voluntarily stutters in the first verse and it is one of the craziest things i have ever heard. Po's (second verse) kills it. The production is sinister as well (thanks to Buckwild-see: D.I.T.C. for more production from him). One person i completely neglected to mention...BIG L! Just listen to "Lifestylez of the Poor and Dangerous" for an explanation b/c i probably couldn't do him justice.