You all should go read this article at Slate on "My Humps" by the Black Eyed Peas, from Tommy and Matt. It makes a very important point, that some things in music are just bad and no amount of relativism can save them.
"there are the songs that are just really bad—transcendentally bad, objectively bad." Emphasis original
I would add hypnotically bad to the list. The song comes on frequently when I am watching music videos in the morning and I end up listening to about half of it because I just can't believe that it is being played. I can't believe that anyone would write it, produce it, pay money to make a video for it, or subject anyone in the public to it.
Here is what I think. Music has been developing for a long time and over that time a certain language and discourse has been created around it. There is no reason why music and its discourse developed like it did, but here we are. If you are going to discuss music you tacitly agree to play by these rules and definitions. The weight of music history and theory thrusts "My Humps" into the horrible category. I appreciate that people have different tastes in music, but if we allow this song to be classified as anything other than horrible bordering on criminal then there is no point in discussing music anymore, the whole language surrounding it will be rendered meaningless.
I am not saying that you are not allowed to like "My Humps." Everyone is free to like whatever they want as far as I am concerned. What you are not allowed to do is call "My Humps" good music.