I can't deal with rap. There are a few rap songs I don't mind (Ninja Rap - Vanilla Ice

), but rap as a whole is something I can't even manage to find tolerable. When overpowered subwoofers and/or idiotic white people bouncing to rap are added, or worse, cars bouncing with hydraulics, it becomes something I hate more than most anything else in the world.
Next up is gospal/religious music. Especially the new-age wanna-be-punk-rock religious music bands.
After that comes country. Gotta hate those steel guitars. Honestly though, usually the lyrics don't bother me too much, but it's the sound that does. That obviously country voice, and the banjo+acoustic+steel guitar sounds, very twangy sounding. Don't get me wrong though, I hate the lyrics too.
Finally, the least hated, boy/girl bands. While I hate the boybands for many many reasons, they have how many thousands of chicks who want them (if they weren't gay), and at least their singing is harmonized and typically isn't cringe worthy. As for girl bands, they're typically very hot so at least they're easy on the eyes, the music usually isn't as bad as the boybands, and again, the actual singing usually isn't cringe worthy.