I haven't ever heard anything I like by any of those rap groups/mcs/whatever either. Maybe because most of them just remind me of the Captain Planet rap. I don't hate them though. Fifty Cent is a shitlicker, but Flava Flav is cool by me, I just don't listen to his music.
As for country, even though I never mentioned, I dunno. Cash, an oft-given example, doesn't, imo, fit neatly into the standard idea of country very well, and Dylan is plain and simple folk/folk rock 95% of the time, at least on his best material.
The only thing I hate more than emo is when people think they have one up by pressing emos 'correct' definition. And don't come back at me with the black metal thing either: there are far more fans and bands who use emo to describe stuff like Bullet For My Valentine than ever talked about the older bands like that. Whilst this situation persists, calling such bands emo best communicates to the widest possible audience the meaning I am implying.