Bone Thugs N Harmony - Technically rap but not the crappy genre you're thinking of, they can actually sing and understand words with 3 or more syllables. Imo, they're kinda like PinkFloyd meets Edgar Allan Poe. The rhyme schemes on most of their older songs are impeccably structured.
Tech N9NE - Rap but leaning towards BTNH's sound.
Bob Marley - Reggae
Numbers two and three usually switch around a lot in my top ten but as it stands, I'm into those three the most atm.