If you don't think rap is poetry listen to Sage Francis (Escape Artist, Bridle, Going Back to Rehab + many more songs), Nas (One Mic first and foremost), Atmosphere (Your Glasshouse, Self Hate Bad Dub), GZA (Stay in Line, B.I.B.L.E), RZA (Fury in My Eyes, Glorious Day) for example. They are all good IMO.