SNSD after I heard the song Gee. I found that song really cute and bubbly. :D
It was BIGBANG & 2NE1 with Lollipop, idk i fell in love with T.O.P's perfection www
it was really a bunch of them but the one i remember the most was Run devil run by Girls Generation. then i discovered 2pm and super junior <3
It was U-KISS haha
SHINee - Ring ding dong ring ding dong ring diga ding ding ding xD
It was either f(x)'s Hot Summer or 2NE1's Hate You
I think it was DBSK
It was EXO for me. MID~ 
I was watching You're beautiful and they played Sorry, Sorry. I'm not crazy about Super Junior but that song made me change the way I see pop music and standard beauty in general xD ! 
exo ahaha, but I stayed because of bts
Super Junior. since 2010. 
I still like them up to know :)