W two worlds because of Lee jong suk
It was not a group but the solo artist and the  world famous
PSY - Gangam Style
but then I did not know that it was KPOP nor it came from korea.
The first KPOP song I heard after knowing abt it is
EXO - BABY DON'T CRY and I loved it....
SS501! They're the dorkiest group ever, haha xD
For me it was Super Junior "Sorry Sorry"!!
Mine is TWICE. I'm new to Kpop, just started last year. I'm not into kpop songs until I discovered Cheer Up in a forum on myanimelist. I loved the mv
I fell in love with KPOP back in 2008 and yes with Super Junior. I got to know them thru SJ-M I love "Me" then I went on to their other videos, but the first song I fell in love with was Marry U, even at that time I didn't know the lyrics well all I wanted to do was marry them HAHAHA ^^
I'm not sure whether it was Big Bang or B.A.P - Big Bang was first but B.A.P was more intense. :P I did randomly listen to Kpop songs for a few years before that but I wouldn't say I was a fan before my BB/B.A.P phase.
I think it was Fantastic Baby by Bigbang but I'm not so sure anymore.. It wasn't from one to the other day.. more like a process so idk
T-ARA. Well, Jiyeon specifically. I fell in love with her when I first saw her in God of Study then I started checking out her other works and got into T-ara. Been a Queen for 7 years. :))
Teen Top and "Rocking" specifically.  I don't like the old era of Kpop at ALL.  But it improved somewhere between 2010 and 2012, didn't sound so cheesy and boring lol.
In 2012 Bigbang- fantastic baby
SUPER JUNIOR! back in 2008. My first song was Happiness.
BIGBANG HARU HARU , Yeah i am  old !!