It was hard finding something like this for you because you have watched many dramas but here are my recommandations.
The Master's Sun - the hate part was only one-sided but I'm pretty sure you won't regret watching this one...one of 2013's best dramas!
The Greatest Love - it has 2 of Korea's best actors which I LOVE, Cha Seung Won and Gong Hyo Jin, it's exacly what you're looking for.In the beginning hey just can't stand each other!
Innocent Man - for me this was the melodrama of 2012.I loved it to death...also the characters are really interesting and their love goes through many obstacles.
I Do, I Do - I don't know if you'll enjoy this one but I did.Is light and funny with an age-gap relationship.This was the only drama where I enjoyed Kim Sun Ah acting.Also they hate each other until a point in the story.
Secret Love - the best melodrama of 2013 in my opinion.They don't only hate each other, more on the male side, but he evens tries to mess up with her life because of hate.I was literally glued to the screen.
The Woman Who Still Wants to Marry - I always recommend this one when I have the chance.It's really interesting and cute and at first they really can't stand each other.
Full House - I'm surprised you haven't seen this one...it's the classic love/hate relationship.It was one of my first drama and I have to admit that it was kind of slow but they kept the love triangle until the very end.