i gotta go with k-pop sistar touch ma body and shake it 
Mine was 2pm. I really like all of their songs. As i hear it more I like them more
SS501's Because I'm Stupid... Ah memories... I miss those times
Super junior - sorry sorry
bigbang haru haru <3
The first Kpop I went crazy over with was FT Island... I already knew BIGBANG though that time but I'm into instruments... it was the time that in my country korean tv shows and music wasn't so popular but now... Oh my God! 
was either Kiss - Because I'm a Girl or DBSK - I Never Let Go 
2PM - Go Crazy and BigBang - Bang Bang Bang
B.A.P :)
And then it was Big Bang and they are still my fav. Kpop group
EXO's Growl! The first song I heard and was interested in was Overdose, but Growl was the one that really pulled me in.
For me the song that pulled me into the world of kpop was Exo's Call Me Baby// However I have heard a couple of kpop songs here and there five years prior, but they didn't pull me in XD