I'm a very mainstream kind of person, which isn't bad! I like pop, pop/rock, pop/r&b, basically... anything pop. I also like r&b, rock, foreign music (Korean, French, Japanese, Chinese, Italian, Spanish), Asian folksy music, classical music, the absolutely spectacular works from Joe Hisaishi (he has made the soundtracks to Miyazaki movies), and umm... some other genres too.
One thing that I can't stand is autotune. I understand if it is used ONLY as a simple effect or a small correction on a few notes, but when artists use it ALL the time... it is extremely annoying. I can't stand listening to robots. Artists like Ke$ha, T-Pain, Lil' Wayne, and others like them... awful. Something that I really like about country is that autotune hasn't really penetrated as much as pop, especially pop, and artists still have to know how to sing to succeed in that genre. I still don't really like listening to country music though, only a few select artists that have a country + pop feel.