Depending on where you're from east, west or south , your age <21>30 the list will vary. Vibe.com has created an NCAA style tournament of the greatest ever MC's. You can check it out here. To me lists of the best MC's is really hit or miss. A lot of is depends on your knowledge of hip hop. A hip hop fan from 2000 has a much different perspective than one from 1995 and so on. Personally I think that this best MC gets way too much attention. Who cares whose the best between jay-z, nas eminen tupac biggie or _____________ .(insert your favorite rapper here) Many of these so called best of list are usually a forum for the writer or magazine to champion who they think is the best MC and whoever you say it is there's gong to be legions that will disagree with you so I find these whole best MC debate rather trite and asinine. Also many of these polls wind up being popularity contests so that kind of skews the results.
I'd rather give some space to the MC's who are just as good but not as well known. The MC's that has had some success but not as much as their talent deserves. What follows are three imbeded youtube videos of underrated MC's. I chose these three from youtube because they give you three different musical perspectives on what MC's some people feel are underrated. I say bully for all three. While I may not totally agree on the lists I cosign with the original posters intent. There is more to hip hop than whose the best MC. Take a look and judge for yourself
My list will follow sometime soon. keep yourself tuned in.