Hmm. Well recently I stopped liking kpop (don't ask why) and I've been more into vocaloid. When I was a kpop fan my main groups I loved was SHINee and B.A.P, my favorites were Daehyun and Taemin I still have my B.A.P poster on my wall, I kinda wanna take it down but if I did, my room would feel bare since it's been there so long xD I'm currently looking for something to replace it. The vocaloids I like are probably Kaito and Len because they're cute :3
K-pop, definitely f(x). I like their voices better than others, and I feel like sometimes other groups are a bit too...modified.
The Japanese group I like is Kalafina but I don't really think that qualifies as "pop", haha...
Vocaloid-wise..Miku has the most songs, so she has my favorites, but I prefer Luka's voice, unless the user makes Miku sound more mature (and they rarely do). I'm not good with screechy, high-pitched songs.
I used to listen to a lot of Jpop/Jrock but ever since Gackt went downhill I kind of stopped listening to anything but soundtracks from movies and stuff.