Deadman, to say one genre is better than another genre full stop and say that hip hop is the top genre is pretty ignorant. Not everyone has the same opinion and everyone would have different tastes. I really like rock, everything from the most mainstream rock to the more hardcore underground stuff, but that's a personal preference and obviously you aren't going to agree with me when I say that rock is good, just like I don't really agree that hip hop is good. You want to know why hip hop dominates the radio and mainstream and grammy awards? It's because those songs and acts, well I think atleast, would be easier to listen to for the majority of the mainstream, top 40 audience compared to the stuff I would normally listen to.
If Hip Hop is indeed the top genre, why didn't they take out the song of the year award? That award went to Coldplay - Viva la Vida, by the way.