He'd be in that Top 5-10 range.
Before his death, he was pretty much near the top in comedy as well as being an effective comedian actor. Everybody loved Bernie Mac, and his star in Hollywood was rising, which is why his death is even more tragic because he'd be big time right now.
Bernie is one of those people who was just naturally funny where it doesn't feel like they're reading off a teleprompter or getting lines fed to them; there are only a few comedians who have that kinda aura: Eddie, Martin in his prime, Pryor, Tucker, among others who could make you laugh from just a regular ole casual conversation.
I don't know why this site loves Dave Chappelle so much...longevity doesn't equate to greatness. Chappelle is overrated and only lasted this long because a lot of comedians from his era either fizzled out or just didn't get enough mainstream attraction.
I've never thought Dave Chappelle was funny to the extent people make him out to be; he's kinda corny, and his brand of humor is too cacish. Kinda like Chris Rock.